To protect his right flank, Mr. Obama quickly added the caveat that Iran should know that “we find the funding of terrorist organizations unacceptable” and that “a nuclear Iran could set off a nuclear arms race in the region that would be profoundly destabilizing.” But curiously, he did not repeat the warning he made repeatedly during the campaign that he would never allow Iran to obtain a weapon, or even the nuclear fuel and capability to build one.  It took only a few hours for Mr. Ahmadinejad, during the 30th anniversary of the Iranian revolution, to respond, even using similar language about the need for mutual respect. Whether this comes to anything, or founders on the question of Iran’s race to enrich more uranium even while the two presidents circle each other, is anyone’s guess. But it is bound to make the new government in Israel nervous, and as we have already learned, the clock in Jerusalem is ticking a lot faster on the Iranian nuclear problem than it is in Washington.  As the Times reported last month, a little less than a year ago the Israeli government came to President Bush seeking the bunker-busting bombs, the refueling capability and the overflight rights over Iraq to take out Iran’s main nuclear enrichment plant, at Natanz. President Bush — the man who elevated preemption to a “doctrine” and who declared he would never, ever allow Iran to develop the capability to build a nuclear weapon — turned the Israelis down.  Mr. Bush told Prime Minister Ehud Olmert, now in his last days in office, to wait. A new, American covert effort to disable the Natanz facility, Mr. Bush said, needed time to work. Reluctantly, the Israelis agreed, and when the Bush administration disbanded last month, it was still unclear whether Mr. Olmert had really intended to go ahead with the attack or was just bluffing in an effort to force the United States to deal with the problem.  Now comes the replay, this time with some new players.  Over the weekend Vice President Joseph R. Biden Jr. offered up the warning that Mr. Obama sidestepped on Monday night: If Iran stays on its current course, sanctions will intensify. The subtext of the Israeli election has been even clearer: To various degrees, all the candidates have made clear they plan to take on not only Hamas, but its Iranian sponsors.  And in Iran itself, the June 12 race for the presidency has been energized by the announcement over the weekend by former president Mohammad Khatami, the reformist who never garnered the power or the will to implement much reform, that he wants his old job back. Presumably that’s a relief to Washington, which desperately wants to see President Ahmadinejad sent to an early and permanent retirement, and with him Iran’s proclamations about Israel’s eventual destruction and America’s inevitable decline.  But it was under Mr. Khatami the reformer, of course, that the expansion of Iran’s nuclear ambitions blossomed. If the latest National Intelligence Estimate on Iran’s nuclear ambitions is correct, the push to develop a weapons design (and the suspension of that effort in 2003) all happened on his watch.  Iran’s contention is that its nuclear program is solely for energy production, but many Western countries, the United States and Israel included, say the program is just a cover for attempts to build a bomb.  Mr. Obama’s task over the next few months will be to demonstrate that he can simultaneously make progress with the Iranians and buy a little time from the Israelis. That will require some hard decisions, first among them whether the United States will stick to its insistence that the entire nuclear infrastructure in Iran, down to the last centrifuge, must be dismantled.  It’s almost inconceivable, some of Mr. Obama’s aides acknowledge, that the Iranians will be willing to give up everything needed to produce a weapon. And it is hard to imagine that the Israelis will settle for anything less.
It’s difficult to read Mahmoud Ahmadinejad’s intentions, but there is no question a new dynamic between the United States and Iran is afoot.