Last year, members of the House voted with their party 93 percent of the time, and senators toed the party line an average of 91 percent of the time. But some are splitting from their parties on Iran: Top Democrats are turning on the president, while some Republicans are siding with the administration's warnings against new sanctions.
The leader of the Democratic pushback against President Obama over Iran is Senate Foreign Relations Committee ranking member Robert Menendez of New Jersey. He and Republican Sen. Mark Kirk cosponsored a bill that would impose new sanctions on Iran if talks over the country's nuclear program collapse. On Tuesday, in his State of the Union address, Obama threatened to veto that bill.
"New sanctions passed by this Congress, at this moment in time, will all but guarantee that diplomacy fails, alienating America from its allies, and ensuring that Iran starts up its nuclear program again," Obama said.
Menendez had harsh words for the president at a Wednesday committee hearing on the role of Congress in the Iran nuclear negotiations. The administration's rhetoric on Iran sounds like "talking points that come straight out of Tehran," he said, chiding Obama for "making their case."
Democratic Sen. Tim Kaine, a longtime Obama ally on Iran, also expressed doubts about the Iran talks on Wednesday. "I have a series of very significant concerns," the Virginian said. Among those concerns, he said, is the fact that "Iran is engaged in activity today that should make us be deeply skeptical about their intentions."
Kaine also said Congress should have a say on any deal the Obama administration reaches. "I support the [interim deal], I support the administration's diplomacy, but we have to weigh in," he said.
But just as some Democrats are jumping ship and challenging the president, two Republicans seemed to break with the GOP majority's push for new sanctions on Iran during the committee hearing.
Sen. Jeff Flake of Arizona said he supports the administration's negotiations and pushed back against the proposal for new sanctions. "We often say that the purpose of sanctions is to get parties to the table," Flake said. "They are at the table, and so I'm confused by the notion that some would want to impose additional sanctions while negotiations are going on."
He clarified that he remains skeptical of Iranian intentions, and, like Kaine, said that Congress should get to vote on whatever final deal negotiators reach.
Sen. Rand Paul of Kentucky went further still. He and retiring Sen. Barbara Boxer of California, a Democrat, are drafting legislation to rival the Kirk-Menendez bill, Boxer announced Wednesday. The legislation, which Boxer called a "moderate" alternative to the Kirk-Menendez bill, would allow Congress to consider reimposing suspended sanctions on Iran if the president determined the country was violating existing agreements.
Although the president has promised to veto the Kirk-Menendez bill, its proponents still have a chance of overriding the veto if enough senators are on board. Next week, the Senate Banking Committee will meet to mark up the latest draft of the Kirk-Menendez bill. But with another sanctions bill soon to be introduced and senators splitting from their parties, the math to get to a veto-proof majority will get complicated.