Did Mitt Romney's hawkish posture in Israel last week increase the likelihood of an Israeli attack on Iran? Unlikely. Will Defense Secretary Leon Panetta's visit to Israel to discuss 'various contingencies and how we would respond' hasten the prospect of confrontation over Iran's nuclear program? Probably not. And will Iran capitulate in response to the increasingly painful economic sanctions tightened by the Obama Administration on Tuesday? Don't bet on it. Although surprises are always possible, all indications are that the Iran nuclear standoff will remain locked in an increasingly tense stalemate at least through November's U.S. presidential election. The Obama Administration is tightening the sanctions chokehold in the hope that declining living standards in Iran will force its leadership to accept Western terms for resolving the nuclear dispute. But there's no sign of Iran capitulating, and the two sides negotiating positions are so far apart that they're able to agree only to keep open a perfunctory channel of communication. Iran appears willing to compromise, but only in exchange for compromises from the Western side that President Obama is unable to make in an election year. Instead, he offers Israel and its supporters on Capitol Hill ever-tighter sanctions, and a promise to take military action to stop Iran if it tried to build a nuclear weapon. (Currently it is assembling the necessary infrastructure, but has not moved to build a weapon, nor made a decision to do so.) In a familiar ritual, U.S. officials were last week again pleading for Israel to allow more time for sanctions to impact on Iran, while Israeli leaders expressed their customary skepticism of sanctions and diplomacy in changing Tehran's calculations -- always threatening to take matters into their own hands by bombing Iran. Whereas Obama has vowed to use force only if Iran tries to build a nuclear weapon, Israel insists that Iran can't be allowed to possess the capability to do so -- a capability it already has. Thus the ongoing tension over timetables and red lines between the US and Israel, with Netanyahu insisting that time is running out while Obama insists that, in fact, there's still plenty of time to resolve the issue through sanctions and diplomacy. Defense Minister Ehud Barak, for example, has insisted that Iran's nuclear program can't be allowed to enter a 'zone of immunity' where, even if it hasn't moved to weaponize nuclear material, it has placed enough of its nuclear infrastructure inside the hardened facility at Fordow, buried deep in a mountainside near Qom, to put it beyond the reach of Israel's aerial-bombardment capabilities. Although the 'zone of immunity' is a fuzzy indicator with no time line attached, the implication is that Israel will have to strike before Iran reaches that point or else forfeit its own military option for dealing with Tehran's nuclear program. Romney, looking for votes and donations from pro-Israel Americans, raised eyebrows when one of his aides said that if elected, Romney would 'respect' an Israeli decision to take unilateral military action against Iran. But Israel is not looking for the US to respect a decision to unilaterally strike Iran; it needs the US to do the job. Despite the posturing of Netanyahu and Barak, it's well known that Israel's military capacities are substantially more limited than those of the US, and that the sustained barrage that would be required to delay Iran's nuclear program for even a couple of years might be beyond Israel's capacities. Even with US support, Israel would be isolated diplomatically if it launched a war with Iran, and the sanctions and other follow-up mechanisms required to prevent Iran building nuclear weapons following a strike would likely crumble. Israeli public opinion, moreover, is opposed to a strike on Iran unless Washington was taking the lead. And Israel's military chiefs reportedly also view taking military action at this stage as a mistake. But with little prospect of a diplomatic breakthrough any time soon, Obama is relying simply on escalating sanctions. Next year may be a better moment for diplomacy. The problem, of course, is that Iran responds to the pain of sanctions not by capitulating, but through provocations designed to create a crisis. If that happens in an election year, all bets are off.