Jonathan Schwarz: "Of course, as people with a sophisticated understanding of the law know, there's a huge difference between ignoring the debt ceiling and bombing Libya. For instance: Obama wants to bomb Libya." 

Okay, good point. Obama doesn't care about the power of Congress when it comes to Libya, but he's reluctant to challenge them over the debt ceiling. Didn't see through that one.  

On the other hand, Eric Posner and Adrian Vermeule, writing in the NY Times, think in the end Obama will have to raise the debt ceiling on his own. And the 14th Amendment won't have anything to do with it. 

Wouldn't be the first time. Abraham Lincoln suspended habeas corpus during the Civil War saying that "it was necessary to violate one law, lest all the laws but one fall into ruin." 

Lincoln is also credited with the observation that the Constitution is not a suicide pact. There are worse crimes than violating the Constitution. For example, letting a minority use the power the Constitution grants them to wreak havoc on the world economy. If that's what the Constitution says, then the Constitution needs to be fixed, but first we need to survive.  

Posner and Vermeule continue: "Franklin D. Roosevelt saw this problem clearly, and in his first inaugural address in 1933, addressing his plans to confront the economic crisis, he hinted darkly that 'it is to be hoped that the normal balance of executive and legislative authority may be wholly equal, wholly adequate to meet the unprecedented task before us. But it may be,' he continued, 'that an unprecedented demand and need for undelayed action may call for temporary departure from that normal balance of public procedure.' In the event, Congress gave him the authorities he sought, and he did not follow through on this threat."