President Barack Obama said he's not bluffing about using military action if needed to stop Iran from getting a nuclear weapon. NBC's Andrea Mitchell reports.
Just days before what could be the most consequential meeting of U.S. and Israeli leaders in years, aides to President Barack Obama and Prime Minister Benjamin Netanyahu are scrambling to bridge stark differences over what Washington fears could be an Israeli attack on Iran's nuclear sites.
With tensions between Israel and Iran running sky high, U.S. officials and military analysts are growing concerned that Israel will launch a multi-phase air and missile attack that could trigger waves of retaliatory missile strikes from Tehran.
That could quickly spiral into a regional conflict that would potentially force the U.S. to intervene to protect its interests.
Further complicating Monday's White House talks is a trust deficit between the two men that has been magnified by mounting pressures of the U.S. presidential campaign. Obama's Republican foes are eager to paint him as too tough on Israel and too soft on Iran.
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Netanyahu is coming to Washington to press Obama to more forcefully declare "red lines" that Iran must not cross in its nuclear program, Israeli officials say, even as speculation mounts that the Jewish state could act militarily on its own in coming months.
"If you don't want me to attack now, I want guarantees," an Israeli official quoted Netanyahu telling top Obama aides who visited Jerusalem last month. "If you're saying, 'we'll take care of you', you're not saying that clearly enough."
The White House has signaled that Obama, who has pledged to prevent Iran from building a nuclear weapon but has been vague on how far he is prepared to go, will resist pressure for a public policy shift.
Time running out?
Instead, amid growing signs that U.S.-led international sanctions are starting to take a toll on Iran, he will seek to persuade Netanyahu to hold off on any military strike to give those measures and diplomacy time to work, U.S. officials say.
But Israeli officials say they fear that time is running out for an effective Israeli attack as Iran buries its uranium enrichment program deeper underground.
Monday's meeting was supposed to have been a defining moment for the American and Israeli leaders, a chance to present a united front as international pressure on Iran intensifies.
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Calls for a tougher approach on Iran are also coming from Republican presidential hopefuls, who see Obama as vulnerable on the issue as he seeks re-election and will seize on any public rift with Netanyahu.
Netanyahu will be pushing not only for Obama's acceptance of whatever action Israel decides to take but for stronger language against Iran that goes beyond the "all options are on the table" mantra on U.S. intentions, Israeli officials said.
Washington has been working to convince the Israelis that a go-it-alone attack would cause only a temporary setback to Tehran's nuclear ambitions while possibly plunging the already-volatile Middle East into chaos.
And Obama's aides insist that an explicit U.S. military threat would be counterproductive right now, especially due to the potential for further spikes in global oil prices and the risk that Tehran might backtrack on overtures seen as opening the door to renewed nuclear talks with world powers.
At schools, in shops, and on the streets of big cities and small towns, daily life plays out in Iran.
But a source close to the administration's thinking on Iran told Reuters the president might try to placate some of Netanyahu's concerns in private and could also pledge even more sanctions to tighten the vise on Tehran.
The White House has proposed the two leaders issue a joint statement after they meet, but the idea has yet to be firmed up, an Israeli official said. A show of solidarity on certain issues might help keep differences under wraps on others.
An administration official also would not rule out the possibility that Obama could harden some of his rhetoric on Iran when he addresses the largest U.S. pro-Israel lobby in Washington on Sunday, the day before he sees Netanyahu.
Israel wary of Washington
Despite that, U.S. officials doubt that Netanyahu will go as far as providing assurances that Israel will consult Washington -- its biggest source of military assistance -- before launching any strikes on Iran, which has called for the destruction of the Jewish state.
Even if Obama privately reassures Netanyahu that the U.S. has the firepower to deliver a devastating blow to Iran's nuclear program further down the line, the Israelis have made clear they cannot rely on that commitment alone.
"Anyone who thinks that Israel is not going to make its own decision, particularly on an issue they view in existential terms, is kidding themselves," Obama's former Middle East adviser, Dennis Ross, told Reuters.
One line of thinking within the Obama administration is that keeping it in the dark about any Israeli military plans might be best for the United States since any sign of complicity would inflame anti-American sentiment in the Muslim world.
But even without a direct U.S. role, there will be deep suspicion across the Middle East that Israel would not act without a green light from Washington.
Still, it remains unclear whether Netanyahu will pay much heed to Obama's words of caution.
Some Obama aides remain suspicious of Netanyahu's motives. They are convinced that he would prefer to see a Republican take control of the White House in 2013 for fear that Obama's re-election would give him a freer hand to push anew for Israeli concessions to the Palestinians during a second term.
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Reuters and msnbc.com staff contributed to this report.