The War Powers Resolution is a joint congressional resolution passed in 1973 that defines when and for how long the president can commit U.S. troops to military action. It limits these instances to when a formal declaration of war has been declared, specific statutory authorization, or during a national emergency.
Amash later tweeted that if Obama were to consult him about Syria, he would say military action without congressional authorization "is unconstitutional & violates War Powers Res."
Amash also said that the War Powers Resolution does not give the president the authority to commit troops without congressional authority for 60 days, and said it is "lazy journalism" to claim otherwise.
But according to the full text of the War Powers Resolution, troops can be committed without a declaration of war, and when that happens (either through some statutory authorization or during an emegency), the president must submit a report to Congress on the details of that action within 48 hours.
It also requires the president to terminate such action after 60 days unless Congress has declared war or authorized the use of force.
Amash's tweets surfaced at about the same time that Secretary of State John Kerry said the administration has found "undeniable" evidence that Syria has launched chemical weapons attacks against its citizens, an act Obama has said would cross a "red line" for the United States. Kerry also said Obama is "actively consulting" with Congress on next steps.
Sen. Bob Corker (R-Tenn.) reacted to Kerry's announcement by saying Obama should seek authorization from Congress to deal with Syria.
"I hope they come to Congress for an authorization at some point," he said. "I think you’re going to see a surgical, proportional strike against the Assad regime for what they have done, and I support that."