Harold Meyerson explains in the Washington Post:
To elucidate the mysteries of Washington — in particular, why House Republicans, having compelled the Democrats to craft a Republican-in-all-but-name plan to get a deal on raising the debt ceiling, still don’t want a deal — we turn to the Fable of the Scorpion and the Frog.
A scorpion meets a frog on the bank of a stream and asks the frog to carry him across on his back. The frog asks, “How do I know you won’t sting me?” The scorpion answers, “Because if I do, I’ll drown along with you.” So the frog, bowing to the logic of the scorpion’s answer, sets out across the stream with the scorpion on his back. About midstream, the scorpion stings the frog, who is paralyzed and starts to sink — as does the scorpion. “Why?” the dying frog asks. “Because it’s my nature,” the scorpion replies...
Republicans apparently won’t be satisfied until Obama takes responsibility for all of the national debt, the Bush tax cuts and the Oklahoma heat wave, admits he’s not a citizen and goes back to Kenya.
They may harm themselves and the nation by holding out for that deal. Like the scorpion, though, it’s their nature.
But not all Republicans are scorpions, are they? Well, the ones who aren't are too afraid of the ones who are to stand up for what's right. Why are they so afraid?
Paul Krugman has the answer:
This would, however, probably be the end of these Republicans’ political careers. And the answer is, so?
If you believe that default will quite possibly be a catastrophe — and leading Republicans probably do believe that — their unwillingness to take the action I’ve just described means that they are risking America’s future rather than pay a price in their personal political careers. That’s cowardice on an epic scale, even if it’s the kind of behavior we take for granted nowadays.
One Republican at least is willing to speak up: