WASHINGTON ― The Senate’s top Republican won’t support plans to require Congress to approve military action against Iran, but he signaled he may at least allow a vote on the idea.

Senate Majority Leader Mitch McConnell, R-Ky., said Tuesday that he thinks a proposed amendment regarding Iran would undermine the president in the midst of a crisis. But, in a break with recent precedent of sidelining potentially controversial issues, he is considering allowing a full-chamber vote on the topic.

“We’re not opposed to having the vote, and we are working on having that vote, passing the NDAA [National Defense Authorization Act] and passing a [border spending] supplemental this week," McConnell told reporters Tuesday.

Amid a partisan split over the growing tension between Washington and Tehran, the bipartisan amendment to the massive 2020 NDAA would allow force in the event of an attack on the U.S., its territories or possessions, or its armed forces, but otherwise require congressional approval. It’s sponsored by Sen. Tom Udall, D-N.M., and backed by Republican Sens. Rand Paul of Kentucky and Mike Lee of Utah.

Senate Minority Leader Chuck Schumer, D-N.Y., had been agitating for the vote for days and hailed McConnell’s decision.

“Yes, we can sit down and work out an agreement to have this amendment, it will be voted yes or no, and we will pass the NDAA,” Schumer said. “That’s the way our caucus feels. Our caucus is strongly united that we must, must, must have a vote.”

Yet McConnell’s assent signals he knows the Iran vote will fail and that the GOP can message effectively against Democrats on the amendment itself, said Rick Berger, and American Enterprise Institute research fellow.

In Senate floor remarks, McConnell said President Donald Trump is right to stand up to Iran and pressure it economically. While Trump does not want a war with Iran, the amendment would “gratuitously take options off the table” in the ongoing crisis, McConnell said.

“What is not productive is an effort being promoted by the Democratic leader that would preemptively tie the hands of our military commanders, weaken our diplomatic leverage, embolden our adversaries and create a dangerous precedent,” McConnell said.

The action came as President Hassan Rouhani said the Trump administration had closed the door on diplomatic talks and derided the White House as being “afflicted by mental retardation,” while Trump said an Iranian attack on any U.S. interest will be met with “great and overwhelming force ... overwhelming will mean obliteration.”

Trump’s remarks contrasted with his recent decision to abort a retaliatory strike after Iran shot down a U.S. surveillance drone, saying it was not “proportionate.” In that same vein, he said later Tuesday, he was ready to negotiate with Iran. “Whatever they want to do, I’m ready,” he told reporters.

From Israel, U.S. national security adviser John Bolton said Iran could walk through an “open door” to talks with America but also warned that “all options remain on the table” if Tehran makes good on its promise to begin breaking a uranium stockpile limit set by a 2015 nuclear deal with world powers.

On Capitol Hill, Democrats said that the Iran amendment was meant to show bipartisan opposition to what they saw as a scattershot approach that risks a disastrous war.

“I was here and voted against the Iraq War when the administration was both intemperate and reckless and molded the intelligence to what they wanted to think. We can’t let that happen again, so we have to be outspoken and push for a debate on this,” said Sen. Sherrod Brown, D-Ohio.

“Voters are very concerned that this president will recklessly get us into a war with a country three times the size of Iraq, with a much longer, prouder history than Iraq. What that could mean to our country could be pretty bad.”

Democrats were also weighing whether ― if a vote on the Iran amendment falls through ― they will filibuster the NDAA. It’s essentially a choice between a popular bipartisan bill that shows support for the military or seizing a potentially historic moment to avert disaster.

“If we’re going to take on a conflict of that degree of risk and complexity, we should have more fulsome briefings, a clear strategy from the administration and a conversation here in the Senate,” said Sen. Chris Coons, a Democrat on the Senate Foreign Relations Committee from Delaware.

“In Iraq, the consequences were far greater, far more expensive and far more negative than I think any, including the members who were there, voting at the time foresaw.”

The Associated Press contributed to this report.