A resolution to curb President Trump’s military authority in Iran has enough votes to pass the Senate, leading Democrats announced Tuesday, stating that Maine Republican Sen. Susan Collins will join three other members of the GOP who had previously announced their support for the measure to invoke Congress’ war powers.

“We now have the 51 votes that we need for the version that’s the bipartisan version,” Sen. Tim Kaine (D-Va.), the author of the resolution, told reporters, noting that Republican Sens. Collins, Todd C. Young (Ind.), Mike Lee (Utah) and Rand Paul (Ky.) had decided to join all 47 Democrats in backing the measure.

Collins declined to comment about her vote slightly before Kaine’s announcement, stating that she would release a statement soon.

Kaine has been working with those four Republican senators and others in recent days to make changes to the resolution, which he originally released just a day after Trump approved the strike to kill a top Iranian military commander in Baghdad. Lee and Paul were the first Republicans to declare their support for the measure, after an administration briefing last week they found both frustrating and insulting, noting how officials refused to say when, if ever, they would consult Congress before launching such a strike — and urging lawmakers to fall in line behind the president.

But interested Republicans pressed Kaine to make changes to the original legislation, particularly its many references to Trump and his administration’s stance and past statements regarding Iran. Those have been removed from the amended draft, which Kaine filed last week, and will be ready for a vote on the floor as soon as next week.

But by next week, supporters will be competing for floor time with the impeachment trial calendar, meaning Senate Majority Leader Mitch McConnell (R-Ky.) and Senate Minority Leader Charles E. Schumer (D-N.Y.) have to determine when to carve out time to hold a vote on the measure.

“We will work out the timing, we have to figure out how it intersects with impeachment, but we believe this resolution is the right way to go,” Schumer told reporters Tuesday.

The resolution is “privileged,” meaning that Republicans opposed to the measure cannot block it from coming to a vote once it is “ripe.” It also means that supporters must only secure a simple majority of the Senate, 51 votes, for it to pass.

Kaine said Tuesday that he is continuing to work with other Republican senators to increase support for the measure before next week. But it is almost certain that Trump will veto the measure, and that Congress will not have the votes to override that veto.

The president’s supporters have been bitterly opposed to the war powers resolutions being considered in the Senate and in the House, which last week voted 224 to 194 to pass a similar resolution, with the support of three Republicans. That measure is not binding, however — meaning that the House may have to take up the Senate’s measure in order to send it to the president’s desk.

Despite likelihood of a veto, Trump’s deputies and supporters have argued that votes on war powers resolutions send a negative message to the troops, while projecting seeming support for a regime that has sponsored terrorism that has led to the deaths of U.S. service members. They have also argued that Trump was completely within his rights to order the strike, citing the 2002 authorization for use of military force and the president’s constitutional right to protect military personnel in harm’s way.

Democrats have taken pains to say they believe the Iranian commander, Qasem Soleimani, was a reprehensible figure, as they and the handful of Republicans who have joined them argue that Trump still cannot trample on Congress’ right to declare war.

Kaine’s amended, bipartisan resolution states plainly that “Congress has the sole power to declare war,” notes that it “has not yet declared war upon, nor enacted a specific statutory authorization for use of military force against the Islamic Republic of Iran” and asserts that “the United States Armed Forces have been introduced into hostilities, as defined by the War Powers Resolution, against Iran.”

But it recognizes an exception in cases where the United States is “defending itself from imminent attack.”

Supporters of the war powers resolution argue that the administration has not presented evidence backing up the claim that Soleimani posed an imminent threat to U.S. troops. Senior officials have argued that the strike on Soleimani was both to prevent an imminent threat and to respond to a previous attack by an Iranian-backed group that killed an American contractor in Iraq.