The Dems...especially Mr. Sen. Harry Reid...have beenhoist on their own petard by not raising the debt in December 2010. In the CNN video below, Reid gives two reasons for this.

First--it wouldn't be fair for an overwhelmingly Dem. congress to do so. Oh yeah? Didn't stop them from passing massive spending legislation with that congress over the previous two years.

Second (the real reason)--he wanted to have the Republicans to have "some buy-in on the debt."   In other words, he wanted the Republicans to share the blame for the new debt ceiling and any new spending that would, he expected, accrue from it.

The link is below:
http://www.youtube.com/watch?v=CiA--Nj8eEI&feature=player_embedded