Sen. Marco Rubio (R-FL) reacts to Barack Obama's announcement about revising policies on U.S.-Cuba relations on December 17, 2014 in Washington, D.C.National Journal

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A pair of rebellious foreign policy hawks is on one side, and the party establishment is on the other. In the battle for Senate GOP hearts and minds on a carefully crafted Iran review bill, the establishment appears to be winning.

Many Republicans are ready to rebuff freshman Sens. Tom Cotton and Marco Rubio, who have offered measures that could upturn a broadly popular Iran nuclear review bill. They say Senate Majority Leader Mitch McConnell has no choice but to leave behind scores of other GOP amendments, which still frustrates many who wanted to add their voice to the process.

"I think that that's his only option," Sen. John McCain said of McConnell. "I know he doesn't want to do it. I don't want him to do it, but it seems to me that we could be dragging this out for days and weeks."

Most Republicans don't fault McConnell, who pledged to restore the Senate to regular order when he rose to power. And at least publicly, few are willing to tear into Cotton and Rubio, who pulled a procedural stunt last week by forcing a decision on potential poison pill amendments, including one that would certify Iran's recognition of Israel's right to exist as a Jewish state and another that would require Iran to divulge the history of its nuclear buildup.

The negotiations are ongoing, but Senate Foreign Relations Committee Chairman Bob Corker, who co-wrote the bill, said Monday night that he expected the Senate to finish the bill this week and send it to the House.

"The manner in which they brought those to the floor gave the majority leader no choice but to do what he is doing, which I assume is filing cloture," Republican Sen. Jeff Flake said.  "I would have liked to see it play out and have a few more amendments. I think we all would have liked to have seen that, but it was just impossible given the way it was handled."

Flake said McConnell was working diligently with members to get consent to move forward on another bunch of amendments when Rubio and Cotton made their demand. The expectation in McConnell's Senate was that lawmakers would have access to a full-throttled, old-fashioned amendment process, complete with the occasional poison pill amendments launched from each side of the aisle. But McConnell is learning that there are some limitations to his promise.

Either McConnell can preserve a delicate bill that gives Congress a final say over any nuclear negotiation with Iran, or he can stike a deal to have votes on any number of amendments—including those by Rubio and Cotton, which Republicans and Democrats could say would sink the bill. McCain says he "spiritually" supports Rubio's amendment, but couldn't vote for it.

"We don't want the Democrats to walk," McCain said. "If the Democrats walk, then we're back at square one."

Cotton said Monday that he had "no comment" on where his amendment stood with leadership, and Rubio blamed Democrats for not allowing votes on amendments. Senate Foreign Relations ranking member Ben Cardin pushed back on the assertion that Democrats are to blame if McConnell shuts down the process.

"I don't think that's justified at all," the Maryland Democrat said. "We wanted an orderly consideration of amendments. There were 67 Republican amendments [and] zero Democratic amendments. We had worked through many to try to work through language so that they could be included in a managers' package. We had two votes. We were lining up a third vote. So that's just not true."

Many in Congress would be happy to support Rubio and Cotton's amendments under almost any other circumstances. But tacking on those amendments now could upset the balance of the carefully negotiated bill and almost certainly would get it vetoed by the president.

Fellow freshman Sen. Thom Tillis said his top concern was ensuring that Congress got a vote on a final nuclear deal, even if it was short on amendments valued by his colleagues.

"There are a lot of amendments that have good content in them, but if any of those amendments threaten the underlying bill then I think we have to stay focused on the primary goal," the North Carolina Republican said. "That is to have Congress have the opportunity to review the details of [a deal]."

The powerful American Israel Public Affairs Committee has provided cover to Republicans fearful of appearing on the record against Rubio's amendment. "We know that senators will offer amendments on a wide range of initiatives, many of which AIPAC would ordinarily support," wrote Howard Kohr, the CEO of AIPAC, in an April 28 letter sent to senators and obtained by National Journal. "However, our paramount objective during Senate consideration of this bill is to ensure speedy enactment of the Iran Nuclear Agreement Review Act by preserving its broad, bipartisan support—so that Congress assures itself a seat at the table in deliberations on any nuclear agreement with Iran."

Sen. Lindsey Graham said he's ready for McConnell to move forward and leave the precarious amendment process behind.

"The prize for me is reviewing any deal between the P5 plus one and Iran, not to send messages," Graham said. "I don't think anyone doubts my support for Israel. I don't need to send a message on that."

This article has been updated to clarify Senate Majority Leader Mitch McConnell's options for handling the Iran debate.

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

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