It’s no surprise that Congress wants to keep ducking  its responsibilities to debate and vote on war. Considering the argument that the administration has been making, it’s easy to understand why they don’t want to do anything:
In an address from the Oval Office on Sunday night, President Obama again asked Congress to officially authorize the use of military force abroad. While White House officials have repeatedly said he does not need that authorization, which was previously granted after the Sept. 11, 2001, terrorist attacks, the administration is seeking to project a united front with Congress against the terrorist threat [bold mine-DL].
In other words, Obama will continue the war in Iraq and Syria regardless of what Congress does, and he will keep pretending that he has legal authority to do this even if they never vote on it. The only reason he is even bothering to ask Congress for a new authorization vote is to make a political statement about support for the intervention. Under these circumstances, the debate would be a farce. There would be no danger that the vote might come out “wrong,” and so the debate would be even more heavily skewed in favor of war than it usually is. Congress would be participating in the process with the understanding that its involvement is purely for show, and so I doubt most members would take the debate seriously.
Oddly enough, one reason that many members of Congress don’t want to vote on a resolution is that they are worried about what voting down a new authorization might represent:
Members of both parties, especially the Republicans who control Congress, fear that a high-profile debate followed by a failed vote to authorize force would be a disastrous public display of division, perhaps emboldening enemies abroad. Lawmakers and Mr. Obama were embarrassed in 2013 when Congress did not authorize airstrikes against President Bashar al-Assad of Syria.
Members of Congress wouldn’t have to worry about this if they had done their jobs sixteen months ago and had a proper vote one way or the other at the start of the war. This is a reminder of how absurd the debate over a new AUMF has been all along. No matter what Congress does on a new authorization, the war is going to continue. Any debate is going to have a predetermined outcome: endorsing the war that has already been going on for over a year. That makes engaging in the debate a waste of everyone’s time, and it confirms Congress as a belated rubber stamp for whatever war the president wants to start on his own.
When Obama went to Congress in 2013 to ask for an authorization to attack Syria, there were a lot of misguided arguments that Obama was reviving Congress’ role in starting wars. Since Obama wrongly claimed to have the authority to attack Syria without Congress’ approval, this made no sense at the time, and it still makes no sense. As we can see, the real effect of seeking and failing to obtain Congressional approval two years ago has been to discourage any Congressional involvement in decisions about war. Then as now, the president is interested in Congressional input only if it endorses what he already wanted to do or what he has been doing, and otherwise he would be happy for them to remain idle. For their part, most members of Congress are content to be idle, and the latest illegal war continues for as long as the president wants.