The main reason congress tends, in practice, not to use this authority is that congress rarely wants to. Congressional Democrats didn’t block the “surge” in Iraq, congressional Republicans didn’t block the air war in Kosovo, etc. And for congress, it’s quite convenient to be able to duck these issues. Handling Libya this way means that those members of congress who want to go on cable and complain about the president’s conduct are free to do so, but those who don’t want to talk about Libya can say nothing or stay vague. Nobody’s forced to take a vote that may look bad in retrospect, and nobody in congress needs to take responsibility for the success or failure of the mission. If things work out well in Libya, John McCain will say he presciently urged the White House to act. If things work out poorly in Libya, McCain will say he consistently criticized the White House’s fecklessness. Nobody needs to face a binary
