A look back at the conflict that has overtaken the country.
America’s expected “limited” strikes in Syria could push the country into an even more dangerous and unpredictable downward spiral or even an international crisis, but doing nothing may be unconscionable and has consequences of its own.
Iran says a U.S. strike in Syria will result in disaster in the region.
The United Nations has resumed its visits to sites outside Damascus, but is asking for more time before action is taken. The U.S. and several other allies seem to be on the verge of military preparations, which is causing nations like Iraq to fear retaliatory response. NBC's Richard Engel reports from Antakya, Turkey.
Syria's foreign minister promised the Syrian military would defend against an attack in ways that will “surprise” the world.
Israel said it is putting its missile defenses, including the Iron Dome and Arrow systems, on their highest state of alert.
Hezbollah is fighting hand in glove with the Syrian regime. The group has tens of thousands of rockets just across Israel’s northern border. It could fire them if it fears it's losing its ally.
In Syria, rebels hope foreign military intervention will be just enough to make the regime wobble. They say they’ll be ready with their own offensive to push the regime over the rest of the way.
So what happens in Syria, and around the Middle East in the hours and days after a military strike? A lot depends on how far the United States goes to destabilize President Bashar al-Assad’s regime.
The ‘do nothing’ option
At this point, doing nothing doesn’t sound likely.
If the United States doesn’t respond, as Secretary of State John Kerry suggested Monday, where is the world’s humanity and morality?
Imagine living in the Damascus suburbs now. How would Americans feel if they had just been attacked by gas-filled bombs that choked to death hundreds, including many children, in their beds, and a stronger nation with the power to punish those responsible said, "Sorry, it’s not my problem, but we do feel bad for you"?
Israel Prime Minister Benjamin Netanyahu said, “We remember the ancient principle of the sages, ‘If we are not for ourselves, who is for us?’”
The ‘do little’ option
The United States could launch a symbolic strike, destroying a few arms depots and runways, but that would not significantly change the balance of power in the Syrian war.
Such a strike from the U.S. and a few partner nations would very likely be coupled with strident warnings from American officials, most likely President Barack Obama personally, saying that if chemical weapons were ever used again, there would be greater punishment next time. But can threats after a weak action be taken seriously?
Syrian rebels, and anyone else who opposes President Assad, would be disappointed and demoralized. They would say the United States is afraid of Syria and wants to keep Assad in power. They would say Assad used chemical weapons and only got a slap on the wrist.
They would ask, "How much more suffering do we have to endure before someone helps us?" They would feel truly isolated from the world. Radical groups would have a stronger case to make to Syrians that only al-Qaeda and extremist Islam can protect them.
President Assad could only conclude that he got away with using weapons of mass destruction.
The war would continue. More Syrians would die. Al-Qaeda could grow stronger. And Bashar al-Assad would remain in power.
The do a ‘little more’ option
Rebels would certainly be encouraged by strong U.S. military strikes, especially if they carry on through two to three days. The strikes could help the rebels advance.
But they could also create a false optimism, a belief that the regime is collapsing when in fact it is not. The rebels could throw themselves into battle, hoping their time to finish off Assad had arrived, only to discover that the regime is much stronger than they anticipated, and suffer enormous losses in the days and weeks after an attack.
I’m reminded of Iraqis in 1991. The United States encouraged Iraqis to rise up after Saddam Hussein's army was driven out of Kuwait. Washington assumed Saddam was weak after losing the 1991 Gulf War. Iraqis rose up, but Saddam's troops killed thousands – Iraqis say tens of thousands -- in a counter-offensive.
The do ‘a lot’ option
If the United States -- most likely with other countries including Turkey, France and Britain -- attacks military targets in Syria in a major way, it could knock the weakened Syrian regime off its last legs. The regime now is heavily dependent on Hezbollah and Iran to keep the war going. Most of the government’s attacks are launched from a distance, by missiles and helicopters. The army rarely sends in troops for face-to-face combat. Resupply is a problem. So is the risk of defection.
If the Syrian regime starts to collapse, the fighting could get very intense. Assad, in desperation, could use more chemical weapons. The regime could decide to fight to its last breath. We could enter a phase of battles more horrific than any yet seen in the Syrian war.
Syria could break into regions, some controlled by Alawites loyal to the military and the Assad family, others controlled by Kurds, and still more run by Sunni rebel factions, including the al-Qaeda linked "Islamic State," which is rapidly replacing the Nusra Front as the most powerful radical group in Syria.
There could be ethnic and sectarian fighting. In this scenario, the regime would break apart as heavy fighting rages. The United States would have to hope that its ally in Syria, the Free Syrian Army, would prevail amid the chaos.
Internationally, Iran seems unlikely to risk a confrontation, but Hezbollah, fearing the loss of its regional ally, could decide to play for public support in the Arab world by attacking Israel. Israel would respond. Lebanon would suffer major losses.
If Syria collapses completely, the United States and the world would have to consider who, and what, fills the vacuum.