Kerry Defends Iran Nuclear Deal Before Skeptical Senate

WASHINGTON — After four and a half hours of contentious questioning, three cabinet secretaries deployed Thursday by President Obama to the Senate to defend his nuclear deal with Iran appeared to keep Democrats largely lined up as a bulwark against Republican opposition.

The hearing before the Senate Foreign Relations Committee was the Obama administration’s first public defense of the agreement before Congress since it was unveiled this month. Secretary of State John Kerry, Energy Secretary Ernest J. Moniz and Treasury Secretary Jacob J. Lew parried questions — at times hostile — as they tried to stave off a resolution of disapproval that could come before lawmakers in September.

Mr. Kerry told skeptical lawmakers that the recently negotiated accord was the only chance to curb Iran’s nuclear ambitions, and that failure to enact the agreement would isolate the United States internationally.

“If the U.S., after laboriously negotiating this multilateral agreement with five other partners, were to walk away from those partners, we’re on our own,” Mr. Kerry told the committee. A congressional rejection of the accord, he said, would amount to “a great big green light for Iran to double the pace of its uranium enrichment, proceed full speed ahead with a heavy water reactor, install new and more efficient centrifuges, and do it all without the unprecedented inspection and transparency measures that we have secured.”

As Mr. Kerry defended the deal, President Hassan Rouhani of Iran told his own domestic critics that the alternative would be an economic “Stone Age.”

Speaking frankly about the toll crippling international sanctions have had on the Iranian economy, Mr. Rouhani said a nuclear deal was precisely the reason he was elected two years ago.

While Republican opposition in Washington appeared implacable, the White House could take heart that Democrats held their fire. If congressional leaders proceed with a resolution to shoot down the Iran deal, Mr. Obama needs Democrats to sustain a promised veto of the resolution.

At the hearing, only Senator Bob Menendez, Democrat of New Jersey and a longtime critic of the Iran negotiations, openly opposed it.

Others, like Senator Tim Kaine, Democrat of Virginia, were far more supportive. “This is a deal that produces a dramatically better position for 15 years than the status quo,” Mr. Kaine said, though he did ask pointed questions on what would happen after that period.

The hearing also served as a platform for presidential politics, with Senator Marco Rubio of Florida, one Republican presidential candidate, warning that the next administration would be “under no obligation” to abide by the deal, while another White House hopeful, Senator Rand Paul of Kentucky, adopted a more measured tone.

For his part, Senator Bob Corker, Republican of Tennessee and the committee chairman, revealed a level of deep skepticism that he had tried to keep in check. “What you have done is codify a personally aligned pathway for Iran to get a nuclear weapon,” Mr. Corker said. “I believe you’ve been fleeced.”

Beyond the politics, the testimony at times revealed facts about the agreement and its potential consequences that had not been widely shared. Mr. Lew, for instance, said the Treasury Department has estimated that the lifting of sanctions would give Iran’s government access to around $50 billion — not the $100 billion widely reported — because half of Iran’s frozen assets have already been obligated, including for projects with China.

“Iran is in a massive economic hole from which it will take years to climb out,” Mr. Lew said.

A new point of contention also emerged over a separate, and confidential, side agreement between Iran and the International Atomic Energy Agency regarding inspections of a facility called Parchin, where Iran is suspected of carrying out prohibited work on high explosives related to the development of nuclear weapons.

Under that side agreement, Republicans charged, Iran would be responsible for taking the samples, which Mr. Corker likened to asking athletes to mail in their own urine samples for drug testing.

Senator Jim Risch, Republican of Idaho, said, “Even the N.F.L. wouldn’t go along with this.” Both Mr. Corker and the committee’s ranking Democrat, Senator Benjamin L. Cardin of Maryland, demanded that the agreement be shared with Congress.

The Obama administration says it does not have a copy of the side agreement. But Mr. Kerry said American officials had been briefed on the details, which he did not disclose, and believed the arrangement worked out by the atomic energy agency can work — with, he hinted, a few adjustments suggested by Mr. Moniz.

Mr. Moniz also defended a provision in the deal that sets a 24-day deadline for resolving disputes between Iran and the atomic energy agency over access to suspicious sites.

The energy secretary said any work involving nuclear materials could not be covered up over three-week period, but he acknowledged that non-nuclear work — such as research into high-explosive triggers that could be used in nuclear weapons — would be harder to detect.

Olli Heinonen, a former deputy director of the atomic energy agency, told Congress on Wednesday that a 24-day deadline might enable the Iranians to remove the evidence of some important nuclear work at small-scale sites before the inspectors gained access.

“Twenty-four days do not cover credibly all plausible scenarios,” he said.

Still, the three cabinet secretaries were unequivocal in their statements that the accord was the best that could be achieved and that without it, the international sanctions regime would collapse.

Mr. Kerry mocked the belief in “some sort of unicorn arrangement involving Iran’s complete capitulation” as “a fantasy, plain and simple.”

That certitude — and the uniform animus of Republicans — seemed to embolden Democrats. Senator Barbara Boxer, Democrat of California, chastised Senators Corker and Risch for “being disrespectful and insulting.”

Senator Tom Udall, Democrat of New Mexico, said he sided with the experts at the nuclear weapons laboratories in his state, Los Alamos and Sandia, who helped devise the inspection and verification regimes.

Senator Chris Coons, Democrat of Delaware and a skeptic of the deal, said, “I do wonder what the alternative is.”

Democratic support is vital. Under the Iran Review Act signed in May, Congress has 60 days to examine the accord, then must decide whether to pass a motion of approval or disapproval — or do nothing. Mr. Obama has said he will veto any congressional move to disapprove the accord, meaning 34 Senate Democrats or 145 House Democrats could sustain that veto and ensure the deal goes into force.

To that end, the president met in the White House Cabinet Room on Thursday with about a dozen undecided House Democrats who he believes could be influential in holding the line on a veto.

“I was struck by how passionately engaged in this issue the president is,” said Representative Adam B. Schiff of California, the ranking Democrat on the House Intelligence Committee, who attended the meeting. He remains undecided, and said after the meeting that a large enough group of Democrats remained on the fence to make a veto override still very possible.

One Republican, Senator Jeff Flake of Arizona, appeared at least open to considering the accord.

“I’m not looking to play ‘gotcha’ at all,” he told the cabinet secretaries. “I’m in support of these negotiations.”

Mr. Paul, a libertarian-minded Republican perhaps seeking to separate himself from the bellicose responses of other presidential hopefuls, was also circumspect.

“I continue to support a negotiated solution and think it preferable to war,” he said.