WASHINGTON – This weekend’s Iowa Republican straw vote signals that the preliminaries are almost over for the 2008 presidential nomination process. And the question is whether Republican candidates have forgotten what comes afterward: a general election.

Ever since the race began taking form last winter, the awkwardly large number of real and pretend aspirants to succeed George W. Bush as the standard-bearer for the GOP have behaved as if they were vying for the endorsement of Bush and Dick Cheney.

An endorsement is not likely to be forthcoming, and it’s questionable how much it would be worth, given the historically low approval ratings those two share. But the rhetoric of most of the 2008 hopefuls, as they campaigned last week in Iowa, suggested a full embrace of Bush-Cheney orthodoxy, not only on terrorism and Iraq but even on the threat to veto a bipartisan Senate bill on children’s health insurance.

The standard rationale for this odd behavior is the observation that nearly 75 percent of those who are likely to vote in the coming Republican caucuses and primaries are still loyal supporters of the administration.

Charles Black, a consultant to John McCain’s campaign, told National Journal’s James Barnes that the continued loyalty of core Republicans means “you’ve got to be a little bit careful about straying away” before cinching the nomination.

McCain, Mitt Romney and Rudolph Giuliani have all had starring roles in the conventions that twice nominated Bush and Cheney, and none of them has shown any impulse to separate himself from his past testimonials to the sterling leadership of the embattled incumbents. Quite the contrary. Romney rarely misses an opportunity to salute the president’s fortitude; Giuliani is as dismissive of Democratic efforts to shorten the war in Iraq as Bush is himself; and McCain, who has seen his fervent advocacy of the surge strategy undercut his standing with independents, never wavers.

The man in the wings, former Tennessee Sen. Fred Thompson, has said less on Iraq than any of the others, but he is eagerly courting the Bush-Cheney conservatives in the South, so his eventual positioning seems dictated by that strategy.

Which suggests that next winter, one of these men may face an interesting dilemma. How do you reposition yourself after hugging Bush and Cheney for a solid year? What do you do to become suddenly the candidate of change?

The one thing on which the polls are clearest today is that this country is ready to turn the page on the Bush-Cheney experience. If ever there has been an administration which has outstayed its welcome, exhausted its energies and spent most of its original ideas, it is this one. People on the inside are holding on by their thumbs, and the country’s patience is about exhausted.

Almost without trying, the Democrats can represent change. Their challenge will be to remove the element of risk or danger from that change.

That is always a crucial test for the opposition party.

But without preparing the ground in the nomination fight, it will be very difficult for Republicans to argue plausibly how they will be different from Bush.

History suggests the right answer and the wrong answer. The right answer was furnished by Ronald Reagan and George H.W. Bush in 1988. The country was ready for change after two terms of Reagan, who had been weakened by Iran-Contra. Bush said he would be a “kinder, gentler” conservative. And Reagan, brilliantly, argued, “We are the change,” reminding voters how much he had already altered the political landscape of America. Bush went on to win.

The wrong answer, highlighted by Barnes in his National Journal article, was offered by Lyndon Johnson and Hubert Humphrey in 1968. Johnson held Humphrey, his vice president, captive to his escalation in Vietnam all the way to the end of the Democratic National Convention, where John Connally bluffed Humphrey out of endorsing the “peace” plank by threatening a walkout. It was not until Election Day was barely a month off that Humphrey declared his independence by advocating a halt in the bombing of North Vietnam – and then it was too late. Richard Nixon won.

Which path do this year’s Republicans choose, 1968 or 1988?