The US Senate on Thursday approved a draft resolution that won the approval of the Democratic and Republican parties, to restrict President Donald Trump's powers to carry out military action against Iran, only after the approval of Congress.
The move comes amid growing concern about escalation with Iran, in the wake of the assassination of General Qassem Soleimani, commander of the Iranian Revolutionary Guard Corps in Iraq last month, and at a time when members of Congress in general are discussing how they can have more influence in US foreign policy.
Eight members of Trump's Republican party voted with the Democratic minority, bringing the number of supporters of the decision to 55 compared to 45 opponents. The bill is now referred to the House of Representatives, and its approval is almost guaranteed in light of the Democrats' domination of the House.
Trump is likely to use his veto against this move, as he has ridiculed the restrictions limiting the president's powers to wage war as an indication of "weakness".
The president recently vetoed the "war powers decision" bill on Yemen.
Increasingly, Congress is seeking to use the 1973 "War Forces Resolution" law to rein in the White House.
"The last thing we need is another, prolonged, and unintended struggle in the Middle East," said Republican Senator Mike Lee, who supported the draft.
The 1973 law was passed as the war in Vietnam came to an end, and Congress was then in increasing anger over the endless conflict, as it is now.
The draft resolution contained an amendment, commending the strike that resulted in the assassination of Qassem Soleimani, and a reference to the injury of more than 100 American soldiers in an Iranian counter-attack.