Andrew Leonard doesn't believe the GOP is dumb enough to go through with a government shutdown. Stan Collender isn't so sure:

[T]he fact that the shutdowns were so bad 15 years ago doesn't automatically mean that they will be equally as politically damaging this time, or for that matter that they'll be damaging at all.  In the current take-no-prisoners/politics of obstruction world that exists inside the Beltway (which definitely did not exist in 1995-96), a GOP-induced shutdown is more likely to be seen by the GOP base as a badge of honor rather than the mark of failure it was before. 

And it definitely would be red meat for the tea party types.

Cantor won't rule it out:

QUESTION: Are you willing to say right now we’re not going to let the country go into default, and we won’t allow a government shutdown?

CANTOR:  Chris, look at this now.  The chief executive, the president, is as responsible as any in terms of running this government.

I think the current GOP, which sees only political war and never political conversation, is capable of anything. Under-estimating their radicalism is as dangerous as under-estimating Palin's appeal.