Polarization, however, is Karl Rove’s specialty. He united his own base on one side — and united his opponents on the other. Al Gore and John Kerry each won 48 percent, the best back-to-back performance by a losing party since the 19th century. Play-to-the-base politics can be a smart strategy — so long as your base is larger than your opponents’.

But it has been apparent for many years that the Democratic base is growing faster than the Republican base. The numbers of the unmarried and the non-churchgoing are growing faster than the numbers of married and church-going Americans. The nonwhite and immigrant population is growing at a faster rate than that of white native-borns. The Democrats are the party of the top and bottom of American society; the Republicans do best in the great American middle, which is losing ground.

Mr. Rove often reminded me of a miner extracting the last nuggets from an exhausted seam. His attempts to prospect a new motherlode have led the Republican party into the immigration debacle.

In my brief service as a speechwriter inside the Bush administration, I often wondered why it was that skeptical experts on issues like immigration could never get even a hearing for their point of view. We took the self-evident brilliance of our plans so much for granted that we would not even meet, for example, with conservative academics who had the facts and figures to demonstrate the illusion of Rovian hopes for a breakthrough among Hispanic voters. We were so mesmerized by the specious analogies between 1996 and 1896 that we forgot that analogies are literary devices, not evidence.

In 2006, Republicans and conservatives paid the price for this we-know-best attitude. I fear that we will pay an even higher price in 2008.

Building coalitions is essential to political success. But it is not the same thing as political success. The point of politics is to elect governments, and political organizations are ultimately judged by the quality of government they deliver. Paradoxically, the antigovernment conservatives of the 1980s took the problems of government far more seriously than the pro-government conservatives of the 2000s.

The outlook is not, however, entirely bleak for Republicans. I notice that much of the Democratic party, and especially its activist netroots, has decided that the way to beat Rove Republicanism is by emulating it. They are practicing the politics of polarization; they are elevating “framing” above policy; they have decided that winning the next election by any means is all that matters — and never mind what happens on the day after that.

If they follow this path, they should not be surprised when they discover that it leads to the same destination.