President Obama says he would “welcome congressional support” but does not need authorization from Congress in order to use force against the Islamic State.  The President appears to have taken no steps to propose actual language to Congress or to move the idea of an authorization along. 

To be fair, the constitutional questions surrounding U.S. military action against ISIS are not easy.  But those wanting Congress to play a larger role in declaring wars, and not simply defer to the Commander in Chief, have a right to be disappointed when Congress, in effect, gave itself a pass and left town early to go home and campaign. 

I had a pretty harsh reaction to the administration’s claim that Congress in the 2001 AUMF authorized force against ISIS in Iraq and Syria.  (For a different view, see Marty Lederman’s post.)  While I think the administration’s interpretation of the 2001 AUMF is unconvincing, I do not believe (as Bruce Ackerman appears to say today in the NYT) that military action against the Islamic State — to date or in the future — is unlawful under the Constitution.  

How should Libertarians respond to the threat from ISIS?