Washington • A Democratic senator says he has at least 51 votes to support a bipartisan resolution asserting that President Donald Trump must seek approval from Congress before engaging in further military action against Iran.

Sen. Tim Kaine of Virginia says the Senate could vote as soon as next week on the measure, which is co-sponsored by two Republican senators and has support from at least two more Republicans.

Republican Sens. Mike Lee of Utah and Rand Paul of Kentucky have co-sponsored the measure, and GOP Sens. Todd Young of Indiana and Susan Collins of Maine said Tuesday they will support it.

The bipartisan resolution "clearly states that America can always defend itself,'' against attack from Iran or any other country, Kaine said, "but we don’t think that this president — or any president — should send our troops into war without a vote of Congress.''

Utah Sen. Mitt Romney was not among the Republicans who said they would support the resolution.

Romney, a member of the Senate Foreign Relations Committee and chairman of the subcommittee dealing with the Middle East, said this is not the time for the balance of powers debate.

“During this time of heightened tensions with Iran, I believe this resolution would undermine our deterrent capability and send the wrong message to Iran,” Romney said, warning that it would “tie the president’s hands.”

Romney said the debate is an important one worth having at a future time.

"However, with American troops in harm’s way, now is not the proper time and this resolution is not the right approach.”

Kaine has long pushed for congressional action reasserting congressional power to declare war, but he said Tuesday he has received renewed support after the Trump administration killed Iran's top general earlier this month. Tehran responded to the U.S. attack by launching missiles at two military bases in Iraq that house American troops. No serious casualties were reported.

Kaine said he has removed, at Republicans' request, language that targeted Trump. Instead the measure is a more general statement declaring that Congress has the sole power to declare war and directing the president to terminate use of military force against Iran or any part of its government without approval from Congress.

Young said in a statement Tuesday that he opposed “a politically charged version” of Kaine’s war powers resolution, but supports revised language reasserting Congress’ constitutional role in debating military action.

"Our service members are willing to put politics aside for our national security, we need to do the same," Young said.

Senate Majority Leader Mitch McConnell and other Republicans oppose the resolution, saying it would send the wrong message to U.S. allies.

The Democratic-controlled House passed a separate war powers resolution last week. The House measure is not binding on the president and does not require his signature. If the Senate approves the Kaine measure, the House could take up the Senate resolution and send it to Trump.

Tribune editor Dan Harrie contributed to this report.