The Obama administration hinted Thursday that it may take elements of an Iranian nuclear deal to the United Nations—while bypassing Congress for now. And that possibility has turned an already ugly political fight over the negotiations even nastier.

In one scenario floated this week, the White House would not immediately put aspects of an Iran deal up for a vote in Congress. Instead, the Obama administration would take aspects of the agreement to the United Nations Security Council—making the U.N. the target of a congressional hatefest.

“The United Nations has no authority whatsoever to bind the United States of America,” Republican Sen. Ted Cruz told The Daily Beast, arguing that only treaties and congressionally-passed laws could do that. “If President Obama attempts to end-run the Constitution by enlisting the United Nations to enforce an Iran deal that sets the stage for Iran to acquire nuclear weapons, it would be both profoundly dangerous to the national security of the United States and our allies, and also patently unconstitutional.”

No deal has yet been reached with Iran. But there were hints that a United Nations process was underway Thursday. Reuters reported that the permanent members of the U.N. Security Council were already negotiating a resolution that would ease U.N. sanctions if a nuclear agreement was reached with Iran.

“If there’s a nuclear deal, and that’s still a big ‘if,’ we’ll want to move quickly on the U.N. sanctions issue,” an official told the wire service.

The existing framework of sanctions against Iran is multifaceted: there are sanctions imposed by the United Nations, by Congress, and through executive actions. While the U.N. could not repeal American domestic sanctions, it could lift existing U.N. sanctions and the White House could use its executive authorities to ease American sanctions.

The State Department insisted that Congress would have a role. But it stopped short of saying when Congress would be asked to weigh in—and because a long-term deal is being negotiated, it could be “a considerable amount of time,” perhaps long after the Obama presidency has ended, when Congress would be asked to vote on easing sanctions.

“It is wrong that Congress will not have a vote. Indeed, Congress will have to vote to lift sanctions at some point during the duration of the deal… once Iran has established confidence with its commitments for a considerable period of time, Congress would be asked to lift sanctions with the benefit of having assessed Iranian compliance with the deal,” National Security Council spokesperson Bernadette Meehan said Thursday.

But if an agreement between the United States and Iran became the basis for a U.N. Security Council resolution featuring sanctions relief, as suggested by former Assistant Attorney General Jack Goldsmith, it could immediately impose legally binding obligations under international law—without the need for congressional approval in the near-term.

“We have no intention of converting U.S. political commitments under a deal with Iran into legally binding obligations through a U.N. Security Council resolution,” the National Security Council’s Meehan said. “[A]ny such resolution would not change the nature of our commitments under [a nuclear deal with Iran], which would be wholly contained in the text of that deal.”

Congressional Republicans—even those that didn’t sign the instantly-infamous letter to Iran about the nuclear deal—were quick to sound the alarm on a pact they say would in effect bypass Congress.

“I just sent a letter to the president requesting that he respond to whether they are in fact attempting to do that,” Senate Foreign Relations Committee Chairman Bob Corker, a Republican, told The Daily Beast on Thursday. “It’s contrary to what we’re attempting to do in Congress, having [our] appropriate role. To me, that’s a direct affront to the American people and to Congress, and I would hope that’s not the route they’re planning to take.”

If the White House were to pursue this course, questions about sovereignty could bubble up to dominate the American political conversation.

“The domestic backlash would be so epic you’d need to dig up Homer just to get someone capable of writing about it,” said Omri Ceren, the media director of the pro-Israel group The Israel Project.

Added GOP Sen. Mark Kirk, “For the United States, the ultimate legitimacy of any international agreement depends on the Constitution, U.S. laws, and our nation’s elected lawmakers, not on unelected foreign bureaucrats.”

But John Bellinger, a former State Department legal adviser during the Bush administration, said he could imagine the Obama administration supporting a U.N. Security Council action “that would lift existing United Nations sanctions (previously imposed by the UNSC) while having no effect on U.S. sanctions.”

If this scenario pans out, Republicans can be expected to raise hell, framing the issue as the White House requesting a U.N. vote before Congress has had a chance to weigh in. But not everyone believes that Congress has the necessity to immediately weigh in.

“Congress may be required to act in some specific cases, and it is certainly nice to have its support, but this is an entirely fictitious role for Congress that any president of either party would rightly laugh at,” said Jeffrey Lewis, a nuclear nonproliferation expert at the Middlebury Institute of International Studies at Monterey.

“Congress is inventing a role for itself that it does not have,” he added. “This isn’t an end run so much as a bunch of people with extremist views on sovereignty being confronted with the fact that their views are extreme.”