And on matters fiscal, the G.O.P. program is to do almost exactly the opposite of what Mr. Bernanke called for. On one side, Republicans oppose just about everything that might reduce structural deficits: they demand that the Bush tax cuts be made permanent while demagoguing efforts to limit the rise in Medicare costs, which are essential to any attempts to get the budget under control. On the other, the G.O.P. opposes anything that might help sustain demand in a depressed economy  even aid to small businesses, which the party claims to love.

Right now, in particular, Republicans are blocking an extension of unemployment benefits  an action that will both cause immense hardship and drain purchasing power from an already sputtering economy. But there’s no point appealing to the better angels of their nature; America just doesn’t work that way anymore.

And opposition for the sake of opposition isn’t limited to economic policy. Politics, they used to tell us, stops at the water’s edge  but that was then.

These days, national security experts are tearing their hair out over the decision of Senate Republicans to block a desperately needed new strategic arms treaty. And everyone knows that these Republicans oppose the treaty, not because of legitimate objections, but simply because it’s an Obama administration initiative; if sabotaging the president endangers the nation, so be it.

How does this end? Mr. Obama is still talking about bipartisan outreach, and maybe if he caves in sufficiently he can avoid a federal shutdown this spring. But any respite would be only temporary; again, the G.O.P. is just not interested in helping a Democrat govern.

My sense is that most Americans still don’t understand this reality. They still imagine that when push comes to shove, our politicians will come together to do what’s necessary. But that was another country.

It’s hard to see how this situation is resolved without a major crisis of some kind. Mr. Simpson may or may not get the blood bath he craves this April, but there will be blood sooner or later. And we can only hope that the nation that emerges from that blood bath is still one we recognize.