Under the US Constitution, the President can not declare war without the approval of Congress. There has always been tension between those two roles, but Mr. Trump's claim that his powers cover military action for something as vague as "vital national interests" is likely to be heatedly debated.
Vice President Mike Pence, who is now on an official trip to Peru, reportedly called congressional leaders to notify them military action was going to be taken on Friday night. However, she said Trump must present a more comprehensive strategy on Syria to Congress and seek lawmakers' approval.
Rep. Justin Amash, a Michigan Republican, said: "These offensive strikes against Syria are unconstitutional, illegal, and reckless. @SpeakerRyan has completely abdicated one of his most important responsibilities". Mr. Pompeo, who is also a Harvard-trained lawyer, had said Mr. Trump had power to conduct the strike under the 2001 Authorization for the Use of Military Force that gave President George W. Bush the power to strike al Qaeda and other worldwide terrorist organizations.
"The last thing I want to see is an AUMF that makes it much more hard for our military to respond to keep us safe, because they have the authority to do that right now", Ryan said.
"What's changed? Zero. They're still using chemical weapons", he said. "They're still using chemical weapons".
His criticism was backed up by, Eric Smallwell, a congressman for California, who tweeted: 'If @realDonaldTrump had time to do the wrong thing (saber-rattling on Twitter), then he certainly had time to do the right thing (consulting Congress) before launching the #Syria strike'. "Americans deserve a voice", Swalwell said. That AUMF has been stretched to cover US action in Libya, Yemen, Somalia, the Philippines and elsewhere.
And Kentucky congressman Thomas Massie ran through a list of questions that had been raised by Trump's action, including "can he strike China, Russia or Britain under the same authority" and "can he bomb Assad's living quarters".
Republican House Speaker Paul Ryan, who on Thursday said Trump had the authority to attack Syria without congressional approval, praised the President's "decisive action in coordination with our allies".
"It's clear that the president has fallen right into a harmful sample of tweeting first and asking questions later, usually basing our most complicated nationwide safety choices on what he is watching on cable information that morning and forcing his employees to scramble to implement coverage in effect", Carbajal, D-Calif., stated.
Sen. Tim Kaine, a Virginia Democrat, went as far as to say Trump's actions were "illegal". "We need to stop giving presidents a blank check to wage war", he tweeted Friday night. Kaine said in a tweet. "Today it's Syria, but what's going to stop him from bombing Iran or North Korea next?"