Trump listens to questions in the Oval Office of the White House [Tom Brenner/Reuters]
The United States Senate backed legislation on Thursday to limit President Donald Trump's ability to wage war against Iran, rebuking the president after a strike against an Iranian military commander and Tehran's retaliation last month raised fears of broader regional conflict.
The measure, authored by Senator Tim Kaine, says Trump must win approval from Congress before engaging in further military action against Iran. Eight Republicans joined with Democrats to pass the resolution by a 55-45 vote.
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Kaine and other supporters said the resolution was not about Trump or even the presidency, but instead was an important reassertion of congressional power to declare war.
While Trump and other presidents "must always have the ability to defend the United States from imminent attack, the executive power to initiate war stops there", Kaine said. "An offensive war requires a congressional debate and vote.''
Trump veto expected if House passes
The Democratic-controlled House passed a separate, nonbinding war powers resolution last month. The House could take up the Senate resolution later this month, said House Majority Leader Steny Hoyer.
Two-thirds votes in the House and Republican-run Senate would be needed to override an expected Trump veto.
Answering a claim by some of Trump's supporters and Trump himself that the measure would send a signal of weakness to Iran and other potential adversaries, Kaine said the opposite was true.
"When we stand up for the rule of law - in a world that hungers for more rule of law - and say 'this decision is fundamental, and we have rules that we are going to follow so we can make a good decision,' that's a message of strength,'' Kaine said.
Republican Senator Mike Lee agreed. Lee supports Trump's foreign policy, including towards Iran, but said Congress cannot escape its constitutional responsibility to act on matters of war and peace.
"What the American people and the entire world will see from the debate we're about to have in the Senate is that there is abundant support for the United States taking tough positions with regard to Iran,'' Lee said Wednesday. "And as part of that, we want to make sure that any military action that needs to be authorised is in fact properly authorised by Congress. That doesn't show weakness. That shows strength.'''
The principle of congressional approval is established for an important reason, Kaine said.
"If we're to order our young men and women ... to risk their lives in war, it should be on the basis of careful deliberation by the people's elected legislature and not on the say-so of any one person,'' Kaine added.
Trump disputed that, arguing in two tweets Wednesday that a vote against Kaine's proposal was important to national security and pointed to the January 3, Trump-ordered drone attack in Iraq that killed Iran's top general, Qassem Soleimani.
"We are doing very well with Iran and this is not the time to show weakness. Americans overwhelmingly support our attack on terrorist Soleimani,'' Trump said.
"If my hands were tied, Iran would have a field day," he added. "Sends a very bad signal. The Democrats are only doing this as an attempt to embarrass the Republican Party. Don't let it happen!''
'Much needed and long overdue'
Tehran responded to the US attack on Soleimani by launching missiles at two military bases in Iraq that house American troops. The attack caused traumatic brain injuries in more than 100 US soldiers, the Pentagon said.
Democrats and Republicans alike criticised a briefing by the Trump administration shortly after the drone strike, saying US officials offered vague information about a possible attack being planned by Iran but no substantial details.
Kaine has long pushed for action reasserting congressional power to declare war. At Republicans' request, he removed initial language that targeted Trump in favour of a generalised statement declaring that Congress has the sole power to declare war. The resolution also directs Trump to terminate use of military force against Iran or any part of its government without approval from Congress.
Republican Senator Susan Collins a co-sponsor, called the resolution "much needed and long overdue".
She said that over the past decade, "Congress has too often abdicated its constitutional responsibility on authorising the sustained use of military force.''
Republican Senate Majority Leader Mitch McConnell and many other Republicans opposed the resolution, saying it would send the wrong message to US allies.