Some senators are very concerned that they weren’t consulted about possibly ending U.S. involvement in an illegal foreign war that they never debated or voted for:
Congress has never debated or voted to authorize the use of force in Syria against anyone. U.S. forces have been operating in Syria for four years with no legal mandate from anyone. The 2001 AUMF has no application here, no matter how many times government officials pretend otherwise. The American presence in Syria does not have the Syrian government’s permission to be there and it is in violation of international law. Ending the previously open-ended, illegal mission is the obvious and necessary correction that has been missing for years. Naturally, hawks all over Washington are having a conniption fit in response to the news that this might actually happen.
President Obama arbitrarily expanded the war on ISIS into Syria in 2014 with no legal authority to do so, but virtually no one in Congress said anything about it then or later. Now that there is a chance that Trump might withdraw U.S. forces from a war they should never have been in, suddenly hawks in Congress are extremely upset about the president’s failure to consult Congress. There are few things that could better illustrate the absurd extent to which illegal presidential warmaking has distorted our constitutional system.
Under the Constitution, Congress should be the branch to decide when and where the U.S. goes to war, and the president then carries out that decision. According to our current practice, the president takes the U.S. to war wherever he wants for any reason, and Congress meekly accepts each new war as it comes. Congressional hawks seem not to have grasped that a president who is allowed to initiate wars on his own authority without their approval will also be able to end them just as arbitrarily without taking Congress’ views into account. When Congress acquiesces in presidential decisions to start illegal wars, they can’t very well complain when a president suddenly decides to end one.
https://www.theamericanconservative.com/larison/live-by-illegal-presidential-warfare-die-by-presidential-whim/