"When I first ran for president, I said it was time for a new era of American leadership in the world, one that turned the page on a decade of war and began a new era of engagement with the world," he said. "As president and as commander in chief, I've done what I've said."
The temporary accord is historic in its own right, marking the most substantial agreement between Iran and the West in more than three decades. The consequences of a permanent deal could be far more significant, lowering the prospects of a nuclear arms race in the volatile Middle East and perhaps opening the door to wider relations between the U.S. and Iran, which broke off diplomatic ties following the 1979 Islamic revolution.
However, Obama and his advisers know the nuclear negotiations are rife with risk. If he has miscalculated Iran's intentions, it will vindicate critics who say his willingness to negotiate with Tehran is naive and could inadvertently hasten the Islamic republic's march toward a nuclear weapon. Obama also runs the risk of exacerbating tensions with key Middle Eastern allies, as well as members of Congress who want to deepen, not ease, economic penalties on Iran.
Despite Obama's assurances that no new sanctions will be levied on Iran while the interim agreement is in effect, some lawmakers want to push ahead with additional penalties. A new sanctions bill has already passed the House, and if it passes the Senate, Obama could have to wield his veto power to keep his promise to Tehran.
Even some members of Obama's own party say they're wary of the deal struck in Geneva.
"I am disappointed by the terms of the agreement between Iran and the P5+1 nations because it does not seem proportional," said Sen. Chuck Schumer, D-N.Y., a close ally of the White House. "Iran simply freezes its nuclear capabilities while we reduce the sanctions."
The Senate's Democratic majority leader, Harry Reid, was noncommittal on the subject of sanctions Monday. On NPR's Diane Rehm Show, he said that when lawmakers return from their Thanksgiving break, "we will take a look at this to see if we need stronger sanctions ... and if we need work on this, if we need stronger sanctions I am sure we will do that."
Some lawmakers are also concerned about concessions the world powers made to Iran on its planned heavy water reactor in Arak, southwest of Tehran. Two congressional aides said that under the terms of the agreement, international monitors will not be able to watch live feeds of any activity at Arak and will instead retrieve a recording from the preceding day during each daily inspection.
The aides were not authorized to provide details of the agreement and demanded anonymity.
On the positive side, Michael Desch, a political science professor at the University of Notre Dame, compared Obama's diplomatic overtures to Secretary of State Henry Kissinger's secret outreach to China in the 1970s, which paved the way for the historic opening of U.S. relations with the Asian nation.
"Then, as now, critics complained that the U.S. was in danger of being hoodwinked by a radical and violent regime that was playing us for a sucker," Desch said. "An opening to Iran could potentially not only contain its nuclear program but set the stage for broader changes there as well."Associated Press writers Jim Kuhnhenn in San Francisco and Bradley Klapper in Washington contributed to this report.