CBS NEWS Washington — President Trump faces a key deadline in the war with Iran on Friday under a decades-old law that limits the use of force without authorization from Congress.

The War Powers Resolution of 1973 lays out a timeline for when lawmakers must be notified of hostilities and when a president is required to withdraw American forces from a conflict in the absence of congressional authorization. 

Under the law, the president is required to give formal notification to Congress within 48 hours of introducing American forces into hostilities, which officially begins a 60-day clock for the president to terminate the use of force unless Congress has declared war or authorized the use of military force. 

The 60-day window 

The Iran war began Feb. 28. Mr. Trump formally informed congressional leaders of the hostilities in a March 2 letter, starting the 60-day clock that expires Friday.

The law allows the president to extend the period for an additional 30 days to safely withdraw forces from hostilities, but it does not grant him authority to continue an offensive campaign. 

“It’s not a 30-day blank check for the president to continue whatever hostilities he sees fit,” said David Janovsky, who leads the Constitution Project at the Project on Government Oversight. 

Friday’s deadline could set up an eventual clash with Republicans in Congress, who have largely been reluctant to break with Mr. Trump on the war, which has extended beyond the four to five weeks he initially predicted without a firm resolution. The fighting has been mostly paused since the U.S. and Iran agreed to a ceasefire on April 8 to allow for talks on a broader settlement.

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