The president conceded during an afternoon news conference that the diplomatic breakthrough only addresses a narrow facet of Iran's disruptive behavior in the Middle East, albeit the one of most urgent concern. But he said that cutting off its nuclear threat would make it "a lot easier for us to check Iran's nefarious activities."
"It solves one particular problem, which is making sure they don't have a bomb," he told reporters in the East Room.
"Will we try to encourage them to take a more constructive path? Of course. But we're not betting on it," he said. "And in fact, having resolved the nuclear issue, we will be in a stronger position to work with Israel, work with the gulf countries, work with our other partners, work with the Europeans to bring additional pressure to bear on Iran around those issues that remain of concern."
Wednesday's news conference came a day after the president delivered a 15-minute early-morning address to the nation to extol the virtues of the deal, which he said represented the best chance to avoid further military involvement in the Middle East.
The agreement between Iran and six world powers led by the United States sets the terms for easing sanctions on the regime if it takes steps to severely reduce its capacity to produce a nuclear weapon and complies with inspections. The accord, sealed in Vienna on Tuesday, represented a calculated gamble on the part of the president that a longtime adversary could be convinced to accept those limits in return for lifting the international penalties that have severely weakened its economy.
Obama challenged critics of the deal both at home and abroad to go beyond rhetoric and propose an alternative that achieves the goal of preventing an Iranian nuke. But he seemed resigned to a political fight.
"Based on the facts, the majority of Congress should approve of this. But we live in Washington," he told reporters.
He and other administration officials have stepped up a campaign to reassure Democrats and other partners as Congress is set to begin a 60-day review period that includes a potential vote of approval or disapproval.
Israeli Prime Minister Benjamin Netanyahu escalated his own campaign against the accord Wednesday, in a series of interviews with American network news anchors.
"I'm making a special appeal to everyone who is concerned with the future of our world," he told NBC's Lester Holt. "To give the preeminent terrorist regime of our time access to nuclear weapons down the line, access to the capacity to make a very large nuclear arsenal with zero breakout time, in a few years, and money to finance terrorists today, I think that is a big, big mistake."
The president said Israel has "legitimate concerns," and he committed to strengthening military and intelligence cooperation, but repeated that he was taking the best path.