The US Congress has passed President Barack Obama's plan to train and arm moderate Syrian rebels to battle Islamic State (ISIL) fighters.
The Senate on Thursday voted 78 to 22 to authorise the first step in Obama's move to degrade and destroy the ISIL group which has conquered swaths of territory in Iraq and Syria. The vote came a day after the House of Representatives approved the legislation.
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Obama thanked Congress for its "speed and seriousness" in endorsing his plan.
"I'm pleased that Congress - a majority of Democrats and a majority of Republicans - in both the House and the Senate, have voted to support a key element of our strategy," he said at the White House.
The measure has been attached to a must-pass, stop-gap spending bill that funds government only until December 11, meaning lawmakers will need to revisit the issue of US military authority in less than three months.
Worries over military involvement
Lawmakers wary of triggering another Middle East war vowed to hold broad use-of-force debates later this year following the November 4 mid-term congressional elections.
"It's important that we give the moderates in the region a fighting chance," Senate Richard Shelby, a Republican, told the chamber.
But he also reflected the broad recognition that US air strikes - already under way in Iraq - and aiding Syrian rebels are merely first steps in what could be protracted US military action.
"There will come a time when more will be required to defeat this enemy. It will not be a short duration," Shelby said.
Just as House lawmakers said prior to their Wednesday vote to authorise the rebel training, some senators complained that Congress was ducking out of Washington this week without conducting a full debate on war authority.
"The Senate needs a real debate about our involvement in Iraq and Syria," Democrat Senator Jon Tester said.
"Are we putting another war in the Middle East on a credit card?"
Obama has pressed Congress to provide him political cover to initiate military action in Syria against ISIL, although the White House and many lawmakers believe he has the constitutional authority to launch air strikes in Syria, as he has done in Iraq, to protect US national security interests.
The Obama administration has insisted its military action is legal under the authorisation of the use of military force (AUMF) that Congress passed in 2001 after the September 11 attacks.