WASHINGTON — At home and abroad, the White House courted support for a landmark nuclear deal with Iran on Thursday as congressional leaders in both parties pointed toward a politically charged showdown this fall over Republican attempts to scuttle the agreement.
"It blows my mind that the administration would agree to lift the arms and missile bans and sanctions," said Speaker John Boehner, R-Ohio, referring to some of the provisions in the complex accord.
He said the Republican-controlled Congress would likely soon be on track to pass legislation denying President Barack Obama the ability to lift numerous financial and other restrictions Iran currently faces.
House Democratic leader Nancy Pelosi of California became the first prominent Democrat in Congress to back the deal, saying she is "very optimistic about our ability to support the president."
Obama has pledged to veto any bill rejecting the agreement. Neither Pelosi nor Boehner ventured a prediction on the final outcome.
The maneuvering in Congress unfolded as Secretary of State John Kerry met with Saudi Foreign Minister Adel Al-Jubeir, coming away without an immediate endorsement for the deal.
"We hope that the Iranians will use this deal in order to improve the economic situation in Iran and to improve the lot of the Iranian people and not use it for adventures in the region," the Saudi diplomat said. His country is Iran's main rival in the Middle East, and Kerry promised to respond if Tehran supports terrorism against its neighbors.
Kerry intends to brief Persian Gulf leaders early next month at a meeting in Qatar. Even before then, Defense Secretary Ash Carter leaves this weekend for the Mideast, with stops in Israel and Saudi Arabia. Officials said his mandate is to reassure the Jewish state that the U.S. is committed to guaranteeing its ally's regional military superiority.
Israeli Prime Minister Benyamin Netanyahu is an implacable opponent of the deal, saying it would put Iran on a path toward acquiring a nuclear weapon.
Under the agreement, Iran pledged to curb its nuclear program for a decade in exchange for potentially hundreds of billions of dollars' worth of relief from international sanctions. Many penalties on the Iranian economy, such as those related to the energy and financial sectors, could be lifted by the end of the year.
At a news conference in the Capitol complex, Boehner spoke strongly against the deal and rebutted one of Obama's central claims over the past two days.
"If President Obama says it's this deal or war, well that's a false choice. The sanctions were working and bringing Iran to its knees," Boehner said. The House, he added, is "going to fight a bad deal that's wrong for our national security and wrong for our country."
Under a bill Obama signed in anticipation of the accord, he has five days to submit the agreement with Iran to Congress. Lawmakers then have 60 days to receive briefings, hold hearings and pass any legislation disapproving it.
Strictly speaking, lawmakers do not have the authority to defeat the deal, but they can block the president from lifting sanctions that Congress has voted to put in place. That, in turn, would let Iran argue that the United States was trying to change a deal, and walk away from it.
In announcing the deal on Tuesday, Obama said he would veto any attempt to change the terms.
In the days since, lawmakers in both parties have largely assumed that Republicans will succeed in passing a measure in September. But it would take a two-third vote in each house to override the veto.
Boehner declined to forecast the outcome. "It's pretty clear to me that a majority of the House and the Senate at a minimum are opposed to this deal. What those numbers look like post-Labor Day, we'll see."
Several Republicans complained that the United Nations is scheduled to vote before Congress on lifting some sanctions against Iran, but there was no evidence that issue would cause Democratic support for the deal to fray.
If anything, it was more likely to become a yet another focus of the 15-way struggle for conservative support among Republican presidential hopefuls. Texas Sen. Ted Cruz, one of the contenders, vowed to would block confirmation of all State Department nominees if the U.N. votes before the 60-day period for Congress to register its opinion.
Wendy Sherman, the lead U.S. nuclear negotiator, said Thursday that even a U.N. vote in favor would not mean sanctions on Iran would come off in that time frame.
While Pelosi was reluctant to predict the outcome of a veto clash, one member of the Democratic vote-counting team was more bullish.
Rep. Jan Schakowsky of Illinois said she believes there's enough support in the House to sustain a veto. As evidence, she cited a letter signed by 147 Democrats earlier this year after world powers and Iran unveiled the general framework of their deal. That letter encouraged the president to continue with the negotiation.
Since the final deal was announced, Schakowsky said, "I haven't heard anyone for example say, 'Oh I learned something that has made it impossible for me now to sustain a presidential veto.'"
Associated Press writers Bradley Klapper, Robert Burns, Deb Riechmann and Laurie Kellman in Washington and Josef Federman in Jerusalem contributed to this story.