Is a Grand Bargain Worthwhile?

A question for Ezra Klein:

As a Clinton administration staffer, a question for Ezra. Suppose we do a bipartisan deficit-reduction deal over the next two years. Why don't you think that the next time the Republican Party gets back into power afterwards they won't do what they did the last time they had working majorities everywhere in 2001-3, and indeed the time before that they had working majorities in 1981-2: large tax cuts for the rich that destabilize America's public finances. It's hard for any veteran of the Clinton Administration to reach any conclusion other than that fixing America's long-run fiscal dilemmas requires first the complete destruction of today's Republican Party, and those of us who care about America's fiscal future need to turn all of our energies to that end. Can you give me reasons not to believe that?