Jonathan Bernstein isn't too worried about Obama side-stepping Congress on Libya. Instead, he fears "cases in which the president authorizes new conflicts in secret":
I'm far more concerned, to tell the truth, about extensions of the "War on Terror" into various locations outside of Afghanistan. Since those actions are covert operations, it's far too easy for the president to keep Congress in the dark. If that's happening, and I worry it is, it's a far more serious violation of the Constitutional balance even if the president could make a decent case that those actions are authorized by Congressional action way back in 2001, because if Congress is ignorant of important actions then Members cannot judge for themselves, as they are entitled to do, whether they want those actions to continue.
The Dish 