This article is from the archive of our partner National Journal

A month ago, the most prominent GOP name in foreign policy was the brash freshman senator Tom Cotton, who spearheaded a controversial letter to Iran's leaders warning that a future president or Congress could jettison a nuclear pact.

But tradition has battled back.

In an old-school display of Senate committee power, Foreign Relations Committee Chairman Bob Corker, aided by Democrats, unanimously steered legislation through the panel Tuesday that hands Congress a major role in any final U.S.-Iran deal to halt the country's alleged nuclear weapons program.

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"I think this is ... the beginning of a United States Congress, certainly a United States Senate, reasserting itself appropriately in foreign policy," Corker—who conspicuously declined to sign Cotton's letter last month—told reporters shortly after the vote.

At a time when Capitol Hill committees' clout has been sapped by gridlock and power grabbed by the parties' leadership, Corker's methodical style has paved the way for one of the biggest congressional assertions of foreign policy power in years.

Senate GOP leaders plan to bring the bill to the floor soon, according to Majority Whip John Cornyn, and the House will take it up after that, House Majority Leader Kevin McCarthy said Monday.

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The bill, which gives Congress the power to formally review the deal and thwart the suspension of congressionally imposed sanctions against Iran, is a victory for Corker and several of his Democratic allies, whom he praised profusely ahead of the panel's vote.

Just hours before the vote, the White House, facing a wave of bipartisan support for the plan and a potential veto-proof majority, dropped opposition to the bill after Democrats and Corker made several changes. Suddenly, in the White House's telling, the measure that had been so problematic before was now a relatively harmless procedural step.

But Corker, at several times during the day, reminded reporters that, in his view, it wasn't tweaks to the bill that backed the White House down.

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"In spite of what may be being said by buildings down the street on the other end of Pennsylvania [Avenue], this legislation is exactly the congressional review we have been working on since Day One," he said during the committee markup.

Corker says the White House knew it was facing momentum for the bill that it could not overcome. "Of course it was saving face. But listen: I'm glad they saved face and came on board," he told reporters after the vote.

The agreement Corker negotiated with the committee's ranking Democrat Ben Cardin and others, to be sure, made several concessions to wary Democrats and the White House.

Sen. Barbara Boxer, who opposed the earlier version of the bill, said the changes agreed to in recent days were important. "I have checked with numerous sources who know, and I have been assured, that this will not disrupt the ongoing agreement," she said in a short interview.

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Changes agreed to in bipartisan talks include a shortening of the congressional review period and nixing language that would have required the president to certify that Iran is not supporting or carrying out terrorism against the U.S. or Americans.

Sen. Tim Kaine, a co-sponsor of the bill who was involved in the negotiations, told National Journal that the broad support among lawmakers for the bill was among several factors that got the White House to drop its veto threat and reluctantly agree to the plan.

"They saw where the votes were going, they did start to get real specific about some changes and they liked them, but I think a point that some of us were making to the White House for some time [is] the issue is not whether Congress will weigh in or not. It is: Do we weigh in under a free-for-all or we weigh in under orderly rules? I think that that point probably became more and more palpable ... to them," Kaine said.

This article is from the archive of our partner National Journal.

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