For the past few months, Mahmoud Ahmadinejad has seemed so pleased with himself. He’s been popping up here and there spouting off about exterminating Israel with the air of a man who thinks he has the world literally over a barrel — who feels himself fully on the offensive and in control.

But that changed yesterday, when Condoleezza Rice announced her willingness to talk with Iran about nukes so long as Iran suspended its enrichment program first. As Robert Kagan of the Carnegie Endowment notes, in a swoop the U.S. has put itself back in front of events. It’s taken the initiative away from Ahmadinejad and Vladimir Putin, and it’s created a series of problems for Tehran.

What Rice did was set off a chain of events that could lead to a U.N. resolution on Iranian sanctions as early as July. Diplomats, book your New York hotel rooms today.

Yesterday’s policy shift really began in late April, as Rice returned from a visit to Baghdad and decided it was time to bring the dispute with Iran to a head. The European Union negotiations were dissolving into disharmony and confusion. There were some indications that Iran was accelerating its nuclear program. It was clear that Iran was winning.

Rice decided to shake things up. What she had to do, to borrow the metaphor of one senior administration official, was to take the cue ball and smash it into all the other balls on the table, and so open up room for future maneuvering.

This in itself was a gutsy maneuver, for in deciding to get so active she was essentially betting her career on her ability to deal with Iran.

Quickly, President Bush and Rice agreed upon a course of action that was neither passivity nor bombing. They decided to accelerate the diplomatic process. They did this with no expectations that Iran would agree to negotiate away its nuclear program. There are no optimists in this administration about the prospects for diplomacy (though there are varying degrees of pessimism).

Instead, Bush and Rice concluded that it was necessary to exhaust diplomatic alternatives, in order to make international sanctions possible later. The U.S. had to remove everybody else’s excuses for inaction.

Bush and Rice told their European and Chinese allies they would be willing to talk with Iran so long as it was in a group, so long as the Iranians suspended their enrichment program, so long as the Europeans agreed to really stick by this precondition, and so long as the Europeans, Russians and Chinese agreed in writing to a menu of sanctions to be imposed if talks never got off the ground.

Reaching agreement on all this was no easy task. And there are some who wonder if the U.S. could have persuaded the Europeans to accept even tougher sanctions. The allies have agreed that if diplomacy fails they will jointly separate Iranian banks from the world banking system, and choke off Tehran’s access to reserve currencies. But there is no mention of an oil or gas embargo. Dennis Ross, the former Clinton envoy, who supports the administration’s course, suggests that Iran will not fundamentally rethink its policy unless it is convinced that the U.S. is so determined to prevent Iran from getting the bomb that it is willing to impose pain on itself.

Still, the accomplishments over the past few weeks have been impressive. Bush and Rice have created a coherent policy. They have organized the Europeans, Russians and Chinese around that policy. They have put Iran on the defensive, and forced the different factions in the regime to argue about what sort of country they wish to become. (Yesterday’s public blast from Tehran was anticipated and discounted.)

Even the rollout was masterful. I called experts around the world yesterday afternoon, and all of them seemed to have just gotten off the phone with a senior administration official (or two), and all were positive about what had been achieved.

It’s still hard to believe the international community can really get its act together. (Have the U.S. and the Russians and the Chinese really forged an agreement on sanctions, or just fudged their differences?) But this display of competence causes me to remember that over the past several weeks this administration has done a number of things well (the nominations of Michael Hayden and Henry Paulson, to name just two). Maybe there’s life in this presidency yet.