I think Krugman nails this one. The Republican deficit hawks don't want to make tough choices - they really do want the government to crash and burn:

Why are Republicans reluctant to sit down and talk? Because they would then be forced to put up or shut up. Since they’re adamantly opposed to reducing the deficit with tax increases, they would have to explain what spending they want to cut. And guess what? After three decades of preparing the ground for this moment, they’re still not willing to do that.

In fact, conservatives have backed away from spending cuts they themselves proposed in the past. In the 1990s, for example, Republicans in Congress tried to force through sharp cuts in Medicare. But now they have made opposition to any effort to spend Medicare funds more wisely the core of their campaign against health care reform (death panels!). And presidential hopefuls say things like this, from Gov. Tim Pawlenty of Minnesota: “I don’t think anybody’s gonna go back now and say, Let’s abolish, or reduce, Medicare and Medicaid.”

What about Social Security? Five years ago the Bush administration proposed limiting future payments to upper- and middle-income workers, in effect means-testing retirement benefits. But in December, The Wall Street Journal’s editorial page denounced any such means-testing, because “middle- and upper-middle-class (i.e., G.O.P.) voters would get less than they were promised in return for a lifetime of payroll taxes.” (Hmm. Since when do conservatives openly admit that the G.O.P. is the party of the affluent?)

At this point, then, Republicans insist that the deficit must be eliminated, but they’re not willing either to raise taxes or to support cuts in any major government programs. And they’re not willing to participate in serious bipartisan discussions, either, because that might force them to explain their plan — and there isn’t any plan, except to regain power.

But there is a kind of logic to the current Republican position: in effect, the party is doubling down on starve-the-beast. Depriving the government of revenue, it turns out, wasn’t enough to push politicians into dismantling the welfare state. So now the de facto strategy is to oppose any responsible action until we are in the midst of a fiscal catastrophe. You read it here first.