WASHINGTON — As far as Congress is concerned, President Barack Obama’s Mideast war strategy isn’t in the clear yet.

The president got what he wanted this past week when the House and Senate overwhelmingly approved arming and training moderate Syrian rebels to fight Islamic State militants. But the go-ahead is good for less than three months. And many lawmakers want a say over the rest of a plan featuring more than 1,600 U.S. military advisers in Iraq and airstrikes expanding into Syria.

Congressional authorization for military action is “long overdue,” said Sen. Dick Durbin of Illinois, the No. 2 Senate Democrat and the most senior member of Congress to question Obama’s legal basis for intervening in the Middle East. “We are living on borrowed time, and we are traveling on vapors.”

A showdown looms when lawmakers return to the Capitol after midterm elections — and no one knows yet how it’s going to play out.

Permission to prepare vetted Syrian opposition units as a ground force to complement U.S. airstrikes expires Dec. 11, at which point the training effort won’t even have begun. American military leaders say the operation needs up to five months to get off the ground. Authorization for the training program is also included in a version of this year’s defense policy bill, but its passage is not guaranteed.