Senate Majority Leader Mitch McConnell faces a tough choice this week on how to move forward with a controversial bill that would allow Congress to review and vote on a nuclear deal with Iran.

The Kentucky Republican promised that when his party took over the Senate, it would change the way the chamber did business and senators would be allowed to offer amendments.

But the filing of a controversial measure from Sen. Tom Cotton (R-Ark.) and presidential hopeful Sen. Marco Rubio (R-Fla.) � which caught McConnell off guard � is putting his promise to the test.
Rubio�s measure would make Iran�s recognition of Israel a part of the nuclear deal between Tehran and the United States. If it becomes a part of the Iran review bill, it would likely torpedo a carefully negotiated agreement between Republicans and Democrats.

McConnell could choose to file cloture on the underlying legislation, which would prevent a vote on the Rubio-Cotton measure by ending debate. Sixty votes would be necessary to do so.

The move would save the Iran bill, but likely generate criticism from conservatives that McConnell is not allowing votes on GOP amendments.

Sen. Bob Corker (R-Tenn.), who spearheaded the Iran legislation, said Rubio�s move all but killed a deal he had been working on to allow votes on a large group of amendments, including one from 2016 presidential contender Sen. Ted Cruz (R-Texas).

�Mitch has a decision now about filing cloture,� he said. �My sense is you'll need to talk with him about what he's going to do."

Some observers believe McConnell will choose to file cloture, which would save the Iran bill and allow the leader to showcase a functional Senate � buttressing a line of argument he wants to use with voters in 2016.

A Senate aide, who said that the Rubio-Cotton move was widely seen as �a bad faith effort,� said that a �substantial� majority is prepared to back Corker�s legislation as is.

�It�s likely at this point that cloture will be filed as early as next week,� the Senate aide said.

McConnell, however, isn�t revealing his cards. His office was tight-lipped on Friday about how he will proceed.

Don Stewart, a spokesperson for McConnell, said that as of Friday afternoon the Kentucky Republican hadn�t announced a decision, and that Republicans were still working on amendments.

If McConnell decides to limit debate on the legislation, it would be a sharp turn from earlier this week when he said he expects a �full and open and robust amendment process.�

Republican Conference Chairman Sen. John Thune (R-S.D.) told reporters earlier this week that he didn�t believe McConnell �has any intention of shutting things down� until after senators �exhaust their opportunity� to debate the legislation.

But that was before Cotton and Rubio attempted to force a vote on the Israel measure.

Democrats twice blocked the Rubio amendment from being formally offered.

Cardin, who opposes it, agrees with Corker that it could derail the international talks with Iran.

�All are bad things,� he said.

McConnell has largely played a backseat role on the Iran legislation, letting Corker and Cardin work with senators to try to bring up and schedule votes on amendments. But Rubio�s hardball procedural tactics puts him squarely back in the drivers seat.

Danielle Pletka, a former Senate Foreign Relations Committee senior professional staff member, said that �from the procedural perspective: McConnell gets to decide. ...I don't envy him.�

�A lot is going to depend on where McConnell comes down. On one hand you can not allow the Senate to devolve into a circus,� said Pletka, who now serves as the American Enterprise Institute�s senior vice president of foreign and defense policy studies. "[But] you cannot, ala Harry Reid, deny senators their right for amendments.�

McConnell could of course avoid the tough choice if Cotton and Rubio back down and accept a deal.

But Rubio is showing no indication that he�s willing to back down. On Friday, he accused Democrats of saying one thing on Israel, but voting another.

�There are a lot of people in the Senate Democratic Caucus who will stand up and argue we want a good deal with Iran, we want to support Israel,� he said at the National Review Institute 2015 Ideas Summit. �But ultimately they're going to support virtually any deal the president signs.�

This article was written by Jordain Carney for The Hill on May 2, 2015.