While political and military analysts sound pretty confident that North Korean leader Kim Jong Un's threats are just bluster, you can't get around the fact that the region encompassing the Korean peninsula is one of the most heavily militarized places on Earth, home to three of the world's six-largest militaries.

If the unthinkable were to happen, how would it play out?

Leon Panetta, who stepped down as President Barack Obama's defense secretary in February, warned this week in an interview with CNBC that "we don't have as much insight as we should with regards to the inner workings of what happens in North Korea."

But based on declassified U.S. and U.N. assessments and independent analyses by military scholars, we can make some educated guesses:

How would North Korea attack?
Probably with a massive ground assault backed by artillery fire. That's because North Korea's standing military, according to the best U.S. and U.N. intelligence assessments, is the fourth largest in the world, at 1.1 million members. South Korea's, by contrast, is about 690,000 strong.

Library of Congress Federal Research Division

That ratio — a manpower superiority of roughly 3-to-2 for the North — is remarkably consistent across calculations of the countries' weaponry, too. By about the same proportion, the North has more tanks, more artillery, more planes, more ships, more missiles. 

In a 2008 report commissioned by the U.S. Joint Chiefs of Staff, the Federal Research Division of the Library of Congress depicted North Korea as, in essence, one giant military installation (see map at right).

How would South Korea respond?
By being smarter and nimbler.

Much of the North's equipment is seriously outdated, going back to its alliance with the former Soviet Union during the Cold War. 

The South's weaponry is less extensive but far more advanced, thanks to modern equipment provided by the U.S. 

"Overall, South Korea's armed forces have become one of the world's more capable militaries and present a formidable forward defense against any possible attack by North Korea," the British-based International Institute for Strategic Studies concluded in 2011.

All of that presumes that North Korean troops could make it into the South in the first place. To get there, they would have to go through about 28,000 U.S. troops stationed along the Demilitarized Zone separating the two countries, supported by about 40,000 more just a short hop away in Japan and on a large military base in Guam.

Doesn't Kim have China to back him up?
In theory, yes, and that's no small matter. 

China's 2.3-million-strong miitary is the world's biggest, outpacing the U.S.'s by almost 40 percent. In its annual report to Congress last year, the U.S. Defense Department didn't estimate how many Chinese forces might be based in North Korea, but it did outline the massive array of forces China is believed to have inside its own borders facing the Korean peninsula:

The map at left depicts China's naval buildup around the Korean peninsula. The map at right details army deployments. Click each map for its full-size version.

But it's not clear that China has the stomach for a fight. Beijing has signaled its displeasure with the North's recent provocations — just last month, it voted for a U.N. resolution to impose sanctions in response to North Korea's announcement of a nuclear test on Feb. 12.

P.J. Crowley, an assistant secretary of state during Obama's first term, told NBC News that Kim's erratic behavior has created major "frustration" in Beijing, which he said "does not want to see an implosion of North Korea."

The U.S., on the other hand, has made it clear that it will defend South Korea. To drive home the point, it sent F-22 stealth fighter jets to South Korea as part of military exercises in a show of force Sunday. And it has sent two warships to the western Pacific to watch for missiles and will soon send an advanced anti-ballistic missile system to its base on Guam, defense officials said.

Military and political analysts say China doesn't want a showdown over the Koreas because then the superpowers' nuclear arsenals become a factor. The U.S. said in an unclassified 2010 report (.pdf) that its stockpile was about 5,100 warheads — more than 20 times that of China, which the Bulletin of the Atomic Scientists estimated in 2011 at 240.

How long could South Korea hold out?
Much longer than the North.

To put it bluntly — as the CIA did in an economic assessment last month — North Korea is a mess internally. Industrial and power output have receded to pre-1990 levels, while frequent crop failures since a devastating famine in 1995 have compounded food shortages that have fueled chronic malnutrition. All that's keeping its people afloat are international food aid deliveries, mainly from China, which would almost certainly be disrupted or cut off in a war.

South Korea, in sharp contrast, boasts a high-tech industrialized economy — one of the 20 biggest in the world, the CIA reported. It has numerous trading partners worldwide to keep it fed and supplied. And because its communications and transportation systems are among the best in the world, it would be much better placed to coordinate civil defense and to move people and material out of harm's way.

So if a traditional assault is unwinnable, what are Kim's options?
Very scary ones.

The Center for International Studies and Research, a nonpartisan French research agency, calculated in October (.pdf) that the North can deploy "a full array of what are typically described as weapons of mass destruction" — one of the biggest chemical and biological stockpiles in the world at 2,500 to 5,000 metric tons, mostly tabun (a nerve agent) and mustard gas.

In a technically secret process, South Korea is believed to have told the Organization for the Prohibition of Chemical Weapons that it had destroyed its chemical weapons in 2008.

And then there are North Korea's own nuclear weapons — the real wild card in the deck.

U.S. officials and other researchers say North Korea may already have a few dozen warheads that could be fitted atop its vast fleet of ballistic missiles. They're fully capable of hitting targets in Japan, South Korea or elsewhere in the northern Pacific, the officials said.

Kim may be bluffing, as his father and grandfather did before him. But those weapons mean he must always be taken seriously.

Mission No. 1, Crowley said, is "figure out a way to denuclearize North Korea."

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North Korean leader Kim Jong Un's brinkmanship is in full bloom. He's ordered the missiles prepped, dismissed the armistice and announced plans to bring a nuclear reactor back on line.

The U.S. response -- a restrained show of force by fighter jets and warships, along with comments that simultaneously decry and downplay the threat -- has not stopped the threats.

Foreign-policy analysts agree the situation is troubling, though there's a deep difference of opinion on what approach would convince Kim to play nice.

Ignore him
The U.S. routine of flexing its muscles whenever Pyongyang lobs another threat Washington's way is playing right into Kim's hands, said Doug Bandow, a senior fellow at the Cato Institute. Like many a parenting expert, he believes the White House should react to North Korea's bad behavior by ignoring it.

Ordering fighter and bomber flyovers meant to show the U.S. means business "just reinforces their behavior," Bandow said. "It gives them attention, showing how this bankrupt, starving country can get a response from the great superpower.

"We are acting as if we are worried about them. To my mind, the response should be, 'Who? Oh, THEM.'"

Yes, Kim could respond to the cold shoulder by ramping up the provocations to get some kind of response, but he's already used up so many that "at some point it's hard to imagine what new threats he could make," Bandow said.

Photos of Kim surveying U.S.-bound missile routes aside, Bandow finds it hard to believe that he's truly the supreme commander "with the power by himself to careen off into war."

"There's nothing to suggest they're suicidal," he said of the regime. But "it's easy to make a mistake" when tensions are escalating fast, he added.

The solution is for the U.S. to disengage. "Why is North Korea our problem?" he said.

KCNA via EPA

In a picture released by North Korea's official news agency, North Korean leader Kim Jong Un convenes an operations meeting March 29 at an undisclosed location where he ordered strategic rocket forces to be on standby to strike U.S. and South Korean targets.

Punish him
Ignoring the threats would be a terrible mistake, according to Gordon Chang, author of "Nuclear Showdown: North Korea Takes on the World," who says the U.S. should be stepping up action against a nuclear-capable North Korea.

He said B-2 bomber and F-22 Raptor overflights should continue, if only to send a message to the South Korean public, which is increasingly losing confidence in America's ability to defend them and pushing for Seoul to develop its own nuclear program, which would destabilize the region.

The time has come for stepped-up interdiction of North Korean shipping and aircraft movements, to stop Pyongyang from selling nuclear technology to Iran with the cooperation of China, he said.

And Chang said the Obama administration should be driving a wedge between North Korea and China by telling Beijing there will be consequences if it continues cozying up to Kim. "North Korea would not be making these threats if they felt like the Chinese were going to clamp down on them," he said.

Chang does not buy the argument that North Korea doesn't have many more tricks up its sleeve, noting that Kim could make good on his threat to shut down the jointly run Kaesong Industrial Region, the main symbol of cooperation with the South.

Hours after this interview, North Korean authorities were not allowing South Korean workers into Kaesong, according to the South Korea's Unification Ministry and Reuters.

Bae Jung-Hyun/Yonhap via AP

A U.S. Air Force F-16 fighter jet lands on the runway during military exercises at the Osan U.S. Air Base in Pyeongtaek, south of Seoul, South Korea, on Tuesday.

The U.S. should one-up Kim's declaration that the armistice in place for 60 years has been replaced by a state of war -- and agree that the armistice is over, so the U.S. is legally able to use force.

"That would shake up the North Korean regime," he said. "It would show there's a new attitude in Washington."

"What I argue for has very substantial downsides, but they are the least worst solutions," he added. "Nobody wants to provoke a crisis, but it's that type of thinking that got us into this situation."

Hug it out
Little more than a year into the job held by his father and his grandfather, Kim has managed to paint himself into a corner -- and the U.S. needs to give him a way out, says Han Park, a University of Georgia professor who has served as an unofficial negotiator in North Korea.

Because he has not consolidated his power at home, the fledgling leader cannot back off. "There has to be a face-saving device," Park said.

"Sanctions will not work. They have never worked," the professor said. "It will aggravate the North Korean leadership even more."

Now that it has some nuclear capability, Pyongyang will not relinquish it unless its security is assured, he said. And the only way to do that is bestowing diplomatic recognition on North Korea and working toward a peace treaty.

Without good-faith talks, Kim will stay on a collision course with the U.S.

"Military confrontation would be unthinkable, but unthinkable things can happen," Park said.

There's no question North Korea would be on the losing end of a conflict, he said. Regardless, "war is something that we cannot afford."

"Giving North Korea peace? What's wrong with that?" he said.

Slideshow: Glimpses into the hermit kingdom of North Korea

David Guttenfelder / AP

As chief Asia photographer for the Associated Press, David Guttenfelder has had unprecedented access to communist North Korea. Here's a rare look at daily life in the secretive country.

Launch slideshow

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Analyst: Threats are predictable, Kim Jong Un is not

This story was originally published on Tue Apr 2, 2013 7:42 PM EDT

Reuters file

A DigitalGlobe Satellite image shows construction at the North Korea's Yongbyon Nuclear complex on Nov. 2010.

SEOUL - North Korea will restart all nuclear facilities including its shuttered Yongbyon nuclear reactor, its official KCNA news service said on Tuesday.

It will rebuild and restart nuclear facilities including its mothballed uranium enrichment facility and the 5 MW Yongbyon reactor which it closed in 2007, KCNA quoted a spokesman at North Korea's atomic energy agency as saying.

It said the nuclear facilities would be used for both electricity and military uses.

Earlier, North Korea's leader appeared to tamp down hostile rhetoric that had threatened impending war with the United States and South Korea in a key speech published Tuesday that implied the isolated country was shifting its focus to development.

Pyongyang has launched relentless verbal attacks and threats against the United States and South Korea since new U.N. sanctions punishing it for its February nuclear test were adopted and during military drills by the South and U.S. forces.

But the speech delivered on Sunday by Kim Jong-Un focused on how nuclear capability supported economic development although it accused the United States of seeking to drag North Korea into an arms race in a bid to hinder its economic improvement.

"It is on the basis of a strong nuclear strength that peace and prosperity can exist and so can the happiness of people's lives," Kim said in the speech delivered to the central committee meeting of the ruling Workers Party of Korea and published in full on Tuesday.

Threats from North Korea have prompted the United States to beef up its forces on the peninsula and station a warship off the Korean peninsula overnight.

US Navy shifts destroyer in wake of North Korea missile threats

North Korea had cut off hotlines between it, the United States, South Korea and the United Nations and threatened to close a joint economic zone it runs with the South. It put its missile forces on full alert and threatened U.S. bases in the Pacific and on the mainland.

The North has promised its citizens that it would become a strong and prosperous nation and is moving towards celebrations of the April 15 birthday of its founder Kim Il-sung, the grandfather of the current leader.

"The fact that this was made at the Party central committee meeting, which is the highest policy setting organ, indicates an attempt to highlight economic problems and shift the focus from security to the economy," said Yang Moo-jin of University of North Korean Studies in Seoul.

The fortress island fixed in North Korea's sights

The 30-year old Kim, who took office in December 2011, said that no nuclear state had been invaded in modern history and that "the greater the nuclear attack capability, the greater the strength of the deterrent against an invasion."

"Our nuclear strength is a reliable war deterrent and a guarantee to protect our sovereignty," he said. 

This story was originally published on Tue Apr 2, 2013 1:38 AM EDT

Analysis

Is Kim Jong Un crazy -- or crazy like a fox?

Analysts said Friday there's a familiar method to the madness coming out of North Korea, where the rookie supreme leader has put rockets on standby, threatened to "settle accounts" with the U.S., and posed near a chart that appeared to map missile strikes on American cities. On Saturday, North Korea said it had entered a "state of war" against South Korea, according to a statement reported by the north's official news agency, KCNA. 

Kim Jong Un's father and grandfather were also serial saber-rattlers when they headed the secretive regime, and experts said there are clear strategic reasons why the world's youngest head of state is ramping up the rhetoric now, after little more than a year in power.

But if the bluster is predictable, the results may not be.

North Korea has enhanced its nuclear capabilities and Kim Jong Un has something to prove to his people and the world. Some outside observers are warning that a misstep, or overstep, by Pyongyang could bring north Asia to the brink of war.

"I think there is always room for miscalculation and things spiraling out of control," said Sung-Youn Lee, professor at the Fletcher School of Law and Diplomacy at Tufts University. "But he is following the playbook set by his father and grandfather."

North Korea is "very adept at engaging at psychological warfare," Lee said. It cranks up the tensions, putting pressure on Seoul and Washington, and is rewarded with aid and concessions when it tones things down, Lee said.

"No leader wants a foreign policy crisis created by North Korea on their hands ... the impulse is to de-escalate," Lee added. "North Korea has been very good at playing this game -- nuclear diplomacy, even extortion -- for the past 20 years."

This time around, foreign-policy watchers said, a confluence of circumstances have set the stage for Kim Jong Un's provocations:

-- Pyongyang is stewing over the U.N. Security Council, with the support of China, tightening sanctions after satellite and nuclear testing that suggested they could one day attack the U.S.

Jon Chol Jin / AP

North Koreans punch the air during a rally at Kim Il Sung Square in downtown Pyongyang, North Korea, in support of their leader Kim Jong Un's call to arms.

-- There are new administrations in South Korea, China and Tokyo, and President Barack Obama is making second-term changes to his defense and national-security leadership, so the timing is right to test the waters.

-- Kim Jong Un may need to consolidate his political power at home. A strong response by the U.S. or South Korea, such as this week's B-2 bomber flyover, helps rally domestic support and distract from economic problems.

-- North Korea's last nuclear test showed progress. "You feel you can afford to threaten because you feel you have a deterrent," said Scott Snyder, senior fellow at the Council on Foreign Relations. 

Joel Wit, visiting fellow at the US-Korea Institute at Johns Hopkins University, said that from the North Korean perspective, Kim Jong Un and his lieutenants "aren't crazy" and are falling back on a tried-and-true strategy.

"They're a very small country dealing with much more powerful countries, and they can't show any weakness. For them, the best defense is a good offense," he said.

Yet Snyder said Kim Jong Un's standing as a new, untested ruler is "the real wild-card factor that makes this different."

The 30-year-old appears to be modeling himself on his grandfather, Kim Il Sung, who is more revered inside the country than the recently departed Kim Jong Il, he said.

"But you have to remember that even though Kim Il Sung came into power in his 30s, the first thing he did was start a war with South Korea," Snyder said.

Stephen Noerper, senior vice president of the Korea Society, noted that 2013 has special significance: it's the 60th anniversary of the armistice that ended that war.

Kim Jong Un's decision to cut the hotline used to arrange cross-border crossing by workers with Seoul was "worrying," he said.

KCNA via EPA

North Korean leader Kim Jong Un at a meeting with his generals where he ordered strategic rocket forces to be on standby to strike U.S. and South Korean targets.

"The wordage is hot and what you don't want is the evolution of a hot conflict," he said. "There should be heightened vigilance even if the expectation is that it will blow over."

A hit on U.S. targets seems highly unlikely and would be "suicidal," Lee said. But South Korea and Japan are within striking distance, and many experts say it's not impossible that Kim Jong Un could act rashly.

"While these weapons can't reach the U.S., it's an extremely tense situation, and wars don't always start logically," Wit said.

Experts were waiting to see the actual impact of North Korea's "state of war" declaration early Saturday.

"Talk is one thing, actions are another," Snyder said.

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• Despite rhetoric from North, South Koreans carry on

PYONGYANG, North Korea -- North Korea's long-range rocket failed early Friday, U.S. officials said, calling it a blow for the reclusive state's propoganda efforts.

The rocket broke up about 90 seconds after taking off, an official told NBC News.

The rocket was launched from Tongchang-ri, on North Korea's west coast and flew about 75 miles, Japanese broadcaster NHK said.

The South Korean army said rocket debris crashed off Kunsan, home to a U.S. air base on South Korea's west coast.

NORAD, the North American Aerospace Defense Command, said the rocket's first stage fell into the sea and two other stages failed.

There were no casualties nor was there any threat to anybody on land, U.S. officials told NBC News.

"All indications are that it failed," one official said, adding that they are still looking into it.

David Guttenfelder / AP

North Korean press center workers are surrounded by international journalists trying to gather news on the launch inside a hotel press center Friday in Pyongyang, North Korea.

The South Korean Defense Ministry announced that North Korea fired the long range rocket Friday morning around 7:39 a.m.

U.S. officials said the launch was monitored by U.S. surveillance satellites, unmanned drones and six anti-missile U.S. Navy warships, NBC News reported. The rocket was also traced by powerful U.S. military radars at sea in the region and in Alaska, NBC News said.

"Despite the failure of its attempted missile launch, North Korea’s provocative action threatens regional security, violates international law and contravenes its own recent commitments," the White House said Thursday night in a prepared statement. "North Korea is only further isolating itself by engaging in provocative acts, and is wasting its money on weapons and propaganda displays while the North Korean people go hungry."

The launch, which North Korea's neighbors and the West said was a disguised ballistic missile test, was to take a three-stage rocket over a sea separating the Korean peninsula from China before releasing a weather satellite into orbit when the third stage was to fire over waters near the Philippines.

Regional powers also worried the launch could be the prelude to another nuclear test, such as one the hermit state conducted in 2009.

North Korea had announced it was planning the launch of an observation satellite to celebrate Sunday's centennial of the birth of Kim Il Sung, the country's late founder.

Hours later, North Korea's state-run news agency said the satellite had failed to reach orbit, and that scientists were searching for a cause of the failure.

"There is not a lot of information being disseminated at this point," said Richard Engel, NBC News' chief foreign correspondent, who is in North Korea. "But we did hear just a short while ago after the launch took place, after it was confirmed internationally, some martial music playing in the street, some fighter jets flying overhead. This is a national celebration time in North Korea and this rocket launch and this satellite launch, as the government describes it, is seen as a source of pride."

Now led by 20-something Kim Jong-un, the third of his line to hold power, North Korea had planned to make 2012 the year in which it became a "strong and prosperous nation" and the launch was part of a program to burnish its credentials.

North Korea's rocket had no impact on Japanese territory, Japanese Defense Minister Naoki Tanaka said.

The United States, Britain, Japan and others have called the launch a violation of U.N. resolutions prohibiting North Korea from nuclear and ballistic missile activity.

The U.S. earlier canceled food aid when North Korea announced the rocket test, despite Pyongyang's February agreement to suspend all tests in exchange for food, NBC News reported.

U.S. military experts told NBC News that the best example of what the North Koreans were denied because of sanctions is advanced electronics for guidance systems, potententially contributing to the failure.

U.S. officials also told NBC News the failed rocket launch was a propaganda effort.

"That effort clearly failed and will have ramifications internally,'' an Obama administration official said.

"This launch was also a chance for North Korea to showcase its military wares to prospective customers," the official said. "The failure will make those customers think twice before buying anything.''

"Their efforts to draw attention to the program certainly seem to have backfired in this case," an official told NBC News. "Everyone will be watching closely to see how the government handles this first real test."

Earlier Thursday, Secretary of State Hillary Clinton said after meeting with Group of Eight foreign ministers that the U.S. would go to the U.N. Security Council to seek action. U.S. Ambassador Susan Rice is the rotating president of the Security Council and controls when to call a meeting.

The U.N. Security Council planned to meet 10 a.m. EDT Friday to discuss the launch, diplomats said.

Rep. Howard P. "Buck" McKeon, R-Calif., chairman of the House Armed Services Committee, said, "Predictably, diplomatic overtures with North Korea have failed once more, and now an avowed enemy of freedom, with a new and unpredictable leadership, possesses nuclear weapons and is testing their capability to strike long-range targets, including the American homeland."

He called for more investment in U.S. national missile defenses.

This article includes reporting by The Associated Press and Reuters.

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Update, 4 p.m EDT Thursday: North Korea launched a long-range rocket early Friday, South Korea's YTN television said, according to a Reuters report.

--

PYONGYANG, North Korea -- North Korea is unlikely to conduct its planned long-range rocket launch on Thursday due to weather conditions, Japan's Kyodo news agency said, citing a government source.

"The weather is poor, and it is now past the launch time given, so there will probably be no launch," Kyodo quoted an unnamed government source as saying.

On Wednesday, an official told Western journalists that fuel was being injected into its controversial experimental rocket "as we speak."

If all goes to plan, the launch, which North Korea's neighbors and the West say is a disguised ballistic missile test, will take a three-stage rocket over a sea separating the Korean peninsula from China before releasing a satellite into orbit when the third stage fires over waters near the Philippines.

Regional powers also worry it could be the prelude to another nuclear test, a pattern the hermit state set in 2009.

"We don't really care about the opinions from the outside. This is critical in order to develop our national economy," said Paek Chang-ho, head of the satellite control center at the Korean Committee of Space Technology, on Wednesday.

Once the refueling has been completed, the North Koreans will have to inject chemicals into the rocket which cause corrosion, which means the firing could come on Thursday, at the start of a five-day window announced already by Pyongyang.

Weather conditions on the peninsula also appear to favor a launch on Thursday or Saturday, according to meteorological reports from Japanese television.

The launch of the Unha-3 rocket, which North Korea says will merely put a weather satellite into space, breaches U.N. sanctions imposed to prevent Pyongyang from developing a missile that could carry a nuclear warhead.

N.Koreans desperate for Western approval of launch

James Oberg, a former rocket scientist with the U.S. space shuttle mission control who is in North Korea, said the rocket was not a weapon, but "98 percent of a weapon", requiring more technology, although not much.

This is the third long-range rocket test by North Korea. It says its second succeeded in putting a satellite into orbit in 2009, although independent experts say it failed.

The firing coincides with the 100th birthday celebrations of the founder of North Korea, Kim Il-sung, whose young, untested grandson, Kim Jong-un, now rules. Kim Il-sung died in 1994.

At a national conference of the ruling Workers' Party, Kim Jong-un was named first secretary, a new post created to give him the official stature to head the state where his grandfather remains "eternal president."

His father was also named party general secretary for eternity at the conference, the North's KCNA news agency said.

Paek, briefing foreign journalists in the North Korean capital of Pyongyang, declined to comment on the launch date.

"As for the exact timing of the launch, it will be decided by my superiors", Paek said.

South Korea, which remains technically at war with the North after their 1950-53 conflict ended with a truce rather than a peace treaty, warned Pyongyang it would deepen its isolation if it went ahead with the launch.

Security sources in Seoul, citing satellite images, have said that North Korea, which walked out of "six-party" disarmament talks three years ago, is also preparing a third nuclear test following the launch, something it did in 2009 and a move bound to trigger further condemnation and isolation.

South Korea holds parliamentary elections on Wednesday, although the rocket does not appear to have been a major issue with voters more concerned about job security.

U.S. Secretary of State Hillary Clinton warned that history pointed to "additional provocations" from North Korea after the launch, an apparent reference to a nuclear test.

"This launch will give credence to the view that North Korean leaders see improved relations with the outside world as a threat to their system," she told cadets at the U.S. Naval Academy in Annapolis, Maryland.

"And recent history strongly suggests that additional provocations may follow."

She also called on China to do more to ensure regional stability.

China, impoverished North Korea's only major ally, on Wednesday reiterated its pleas for calm and said all sides should make efforts to establish peace in the region.

Reuters and The Associated Press contributed to this report.

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Susan Walsh / AP

President Barack Obama speaks at Hankuk University in Seoul, South Korea, March 26. Obama discussed his Prague agenda to stop the spread of nuclear weapons and seek the peace and security of a world without them.

Updated 12:35 a.m. ET: SEOUL – President Barack Obama’s speech at a university that prides itself on diversity and “producing numerous CEO’s and outstanding diplomats” was billed as an update to his comprehensive nuclear energy and nuclear security agenda he set forth in Prague in 2009.

However, even with strong words directed towards North Korea, his commitment to as one White House source put it, “reduce America's nuclear weapons and the role they play in our national security strategy” could prove to be fodder for his Republican rivals back in the states. 

The president said he believes the United States has a “moral obligation” to act and lead the world in reducing nuclear stockpiles.  He continued, “I say this as president of the only nation ever to use nuclear weapons.  I say it as a Commander-in-Chief who knows that our nuclear codes are never far from my side.  Most of all, I say it as a father, who wants my two young daughters to grow up in a world where everything they know and love can’t be instantly wiped out.”

He announced that when he meets with Russian President-elect Vladimir Putin in May he plans on discussing taking steps so that both Russia and the United States reduce, “not only our strategic nuclear warheads, but also tactical weapons and warheads in reserve.”  The president said such a step would have never been taken before.  It is also a step that is sure to be pounced upon by rivals who already see the reductions he is calling for in defense spending as a sign of weakness.

The president also boasted about steps taken in the last few years to “reduce the number and role of nuclear weapons in our national security strategy” and derided the Cold War stockpiles as being ill-suited for combating the type of terrorism America faces.

But while pushing a message that the United States has to lead the world on reducing nuclear weapons and materials throughout the world, he took time to speak directly to Pyongyang about the choice the North Korean leaders have if they continue to provoke South Korea and the rest of the world.

Obama: North Korean rocket test would isolate regime

Echoing his comments from a press conference yesterday he said, “your provocations and pursuit of nuclear weapons have not achieved the security you seek; they have undermined it. Instead of the dignity you desire, you're more isolated.”

He continued, “There will be no rewards for provocations.  Those days are over.  To the leaders of Pyongyang I say, this is the choice before you.  This is the decision that you must make.  Today we say, Pyongyang, have the courage to pursue peace and give a better life to the people of North Korea.”

The reports that North Korea has moved a long-range rocket to a launch pad this weekend, that could be used to carry a nuclear weapon is just the latest provocation that strained new talks between the US and North Korea.

And once again the president seemed to call for the North Koreans to call for a different way of life:

“This much is true:  The currents of history cannot be held back forever.  The deep longing for freedom and dignity will not go away.  So, too, on this divided peninsula.  The day all Koreans yearn for will not come easily or without great sacrifice.  But make no mistake, it will come.”

Obama calls Korean DMZ 'Freedom's frontier'

The speech at Hankuk University comes right before President Obama is scheduled to meet with the leaders of Russia and China where the thorny issues of North Korea, Syria and Iran are expected to be discussed.  Later in the day he will attend the beginning of the international Nuclear Security Summit. The summit includes 53 countries and four international organizations that have pledged a commitment to securing nuclear materials around the world.

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Jeon Heon-Kyun/Pool / EPA

South Korean soldiers stand guard at the Military Demarcation Line in the Demilitarized Zone that separates the two Koreas since the Korean War, in the border village Panmunjom in Gyeonggi-do, South Korea.

President Barack Obama, seeking to increase pressure on North Korea to abandon its atomic weapons, will visit the Demilitarized Zone on South Korea's tense border on Sunday before a nuclear security summit in Seoul.

Obama's visit to the border will be a strong show of support for South Korea, the White House said on Tuesday, sending a message to the North as Washington builds an international effort to get stalled nuclear disarmament talks back on track.

North Korea will not attend the summit, where Obama will meet with Chinese President Hu Jintao and urge him to use Beijing's long-standing influence with Pyongyang, where leadership has recently passed to Kim Jong-un.

"We certainly hope and recommend that China bring all the instruments of power to bear to influence the decision-making in North Korea," said Daniel Russel, White House National Security Council senior director for Asia.

Ben Rhodes, deputy national security adviser, said the trip has two purposes for Obama.

"The first is the focus he has put on nuclear security along with non-proliferation since the beginning of his time in office," Rhodes said. "And the second is, of course, our increased focus on the Asia Pacific as a region of great importance to the United States."

Obama will meet with U.S. troops at the DMZ during the trip, his third to South Korea in three years, White House officials said.

Secretive North Korea has twice tested a nuclear device, and the United States says its long-range ballistic missile program is progressing quickly.

While experts doubt North Korea has the ability to miniaturize an atomic bomb to place atop a warhead, last year Washington warned that the American mainland could come under threat from North Korean missiles within five years.

Last month, North Korea reached an agreement with Washington to suspend nuclear tests, long-range missile launches and uranium enrichment as part of a deal to restart food aid, but then announced it would launch a rocket carrying a satellite to mark the centenary of founder Kim Il-sung's birth next month.

The United States has said this plan could violate the nuclear moratorium deal and scuttle the resumption of food aid.

This article includes reporting by Reuters.

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