If Hill Republicans thought Israeli Prime Minister Benjamin Netanyahu's Tuesday address would build broad support for having Congress review any nuclear deal with Iran, they thought wrong.

By the end of the day Tuesday, key Democratic senators had pulled their support for just such a bill after Majority Leader Mitch McConnell (R-Ky.) announced he was fast-tracking the legislation, bringing it to the Senate floor for debate as soon as next week, short-circuiting committee deliberations that Democrats say are necessary to perfect it.

Bob Corker (R-Tenn.), Robert Menendez (D-N.J.), Lindsey Graham (R-S.C.) and Tim Kaine (D-Va.) introduced the Iran Nuclear Agreement Review Act late last week, which would provide for 60 days of congressional review for any deal that comes out of the pending "P5+1" negotiations in Geneva, where the United States, Germany, Russia, China, Britain and France are now at the table with the Iranian regime. Once submitted to Congress, lawmakers could approve, disapprove, or take no action on the deal. The talks are currently scheduled to end on March 24.

The legislation had not only two Democratic sponsors but four co-sponsors in the Democratic conference, giving the measure a filibuster-proof level of support. But that was before McConnell moved to place the bill on next week's legislative calendar -- guaranteeing a Senate vote while negotiators are still at the table.

"We think the timing is important," McConnell said Tuesday. "We think it will help prevent the administration from entering into a bad deal, but if they do, then it will provide an opportunity for Congress to weigh in."

On Tuesday evening, Menendez, ranking member of the Foreign Relations Committee and a fierce critic of the Iranian regime, went to the Senate floor to withdraw his support for the bill, suggesting that McConnell's move represented an effort to influence or derail the negotiations now underway rather than a bona fide desire to review whatever deal is reached.

"I can't imagine why the majority leader would seek to short circuit the process unless the goals are political rather than substantive, and I regret to say these actions make clear an intention that isn't substantive, that is political," Menendez said. "The majority leader is single-handedly undermining our bipartisan efforts."

Kaine, meanwhile, issued a statement calling the move to send the bill to the floor "contrary to the important interests at stake."

"Premature action also disrespects the ongoing work to build a broad coalition of colleagues in support of this bill," Kaine said. "Congress should weigh in on any Iranian nuclear deal that impacts the statutory sanctions we've enacted. But we need to demonstrate that our review will be thoughtful and deliberate rather than rushed and partisan.”

Meanwhile, Republicans are betting that Democrats, despite the bluster about "regular order" and bipartisanship, aren't going to pass up a chance to review one of the most closely watched diplomatic efforts in years. As Corker said Tuesday, “Surely if you ran for the United States Senate, you would want to have the opportunity to weigh in" on whatever deal is reached.

Regardless, the bill may have left the realm of the substantive on Saturday, when President Obama said he would veto it if passed.