George Bush likes his sleep. While campaigning for the presidency in 2000 his prize possession was a feather pillow. On the night that Saddam Hussein was executed he went to bed at 9pm with strict orders not to be woken. When the then CIA director, George Tenet, tried to alert him to news of the first night's bombing of Iraq he was sent away. "He is the type of person who sleeps at 9.30pm after watching the domestic news," Saudi Arabia's Crown Prince Abdullah told Okaz, a Saudi newspaper.

But one can't help wondering if Karl Rove's resignation might not disturb his slumber for his remaining months in the White House. Rove, Bush's consigliere for the past 30 years, left last week in much the same manner as he had stayed: misleading the public. He told the nation that he wanted to spend more time with his family. Maybe he should have checked with his family first. His only son leaves for college in just a few days.

Rove is leaving because there is nothing more for him to do; Bush is letting him go because he no longer has any use for him. His departure effectively marks the end of the Bush presidency - from hereon in Bush's tenure is about keeping the troops in Iraq and as many of his administration out of handcuffs as possible. Last week Fox News asked the neocon commentator Charles Krauthammer how much time Bush had to promote his agenda. "None," said Krauthammer. "It's over. There is no agenda."

But while the left loves to revel in Bush's woes, it invariably revels in the wrong woes. Bush's problem is not that he has failed on our terms - humanism, equality, peace and democracy - but that he has failed on his own.

True, his low approval ratings reveal a president approaching Nixonian lows. But then, unlike Nixon, Bush has never craved popularity. He pushed through most of his most pernicious legislation after having lost the popular vote in 2000. This is a man who understood 51% of the vote in 2004 as an overwhelming mandate. "I'll reach out to everyone who shares our goals," Bush said. "I earned capital in the campaign, political capital. And now I intend to spend it. It is my style."

True, too, that the Iraq war is going badly. But then it has never been going well, and that has never seemed to bother him either. He has described himself as "the decider", but never "the contemplator". This too is his style.

In any case the Bush agenda was always more far-reaching than anything that can be accounted for by mere polls, war, or the loss of human life. The ultimate aim of his presidency was to realign American politics to cement a conservative electoral majority for a generation. The cornerstone of his domestic agenda was to build on the Republicans' traditional base of evangelists, southerners, white men and the wealthy, by winning over Catholics, married white women and a sizable minority of Latinos with a mixture of policies and pronouncements on immigration, homophobia, abortion and social security.

Bush did not create the partisan split in America; he inherited it, just as Al Gore would have if he had won the supreme court case in 2000. But while the split was broad (the difference was less than 5% in 13 states from New Mexico to New Hampshire), it was Bush who made it deep and rancorous.

For unlike Thatcher or Reagan he sought to achieve his ends not by exploiting division in order to forge a new, more rightwing consensus but rather to exploit new divisions in order to crush a growing consensus. The majority of the country was, for example, pro-choice and in favour of granting equal rights to gay couples in almost all areas. So the Bush administration chose to leverage gay marriage and late-term abortion - two issues that could act as a wedge - to rally his base. Crude in execution and majoritarian in impulse, it sought not to win over new converts but simply to mobilise dormant constituencies. His legacy will be rightwing policies - but not a more rightwing political culture.

That his agenda should have failed so completely should come as no surprise. The project was always, at root, a faith-based initiative. Following the Republican congressional victory in 2002 Rove was asked to comment on the fact that the nation seemed evenly divided between Republicans and Democrats. "Something else is going on out there," he said. "Something else more fundamental ... But we will only know it retrospectively. In two years, or four years or six years, [we may] look back and say the dam began to break in 2002."

With no discernible material basis on which to build, this new majority at home and new world order abroad had to be fashioned from whole cloth. A Bush aide once ridiculed a New York Times reporter for belonging to "the reality-based community", which he defined as people who "believe that solutions emerge from your judicious study of discernible reality". "That's not the way the world really works any more," he said. "We're an empire now, and when we act, we create our own reality. And while you're studying that reality - judiciously, as you will - we'll act again, creating other new realities, which you can study too, and that's how things will sort out. We're history's actors ... and you, all of you, will be left to just study what we do."

So here we are studying. The coalition crumbled. In 2006 Catholics backed the Democrats; white women broke even. According to a Wall Street Journal poll, Americans would prefer the next president to be a Democrat by 52% to 31%. Meanwhile, the presumptive standard bearer for this new majority is treated like a pariah. As the Republican hopeful Mitt Romney pressed flesh in a restaurant in Manchester, New Hampshire, a few weeks ago, Muriel Allard said: "We need someone like him. They don't care about us over there." At a town hall meeting a couple of hours away in Keene, another Republican contender, John McCain, was asked last month if it wasn't time to put a "warrior in chief" in the White House rather than these "draft dodgers". Bush's name never came up. "Friends who were obnoxious in their praise for him just don't mention him any more," says Rick Holmes from Derry. "He's like the embarrassing uncle you just don't want to talk about."

A sense of doom among Republicans is palpable. A growing number of Republican congressmen - most recently the former house speaker Dennis Hastert - have announced they are to retire, or are considering it. "Democrats will win the White House [and] hold their majority in the house and in the Senate in 2008," the retiring congressman Ray Lahood told the New York Times.

There is even talk that Republicans might not invite Bush to their convention. "If they're smart, no," the Republican pollster Tony Fabrizio told Newsweek. "Especially if things don't change in Iraq, we'll have the problem the Democrats had in 1968 with Lyndon Johnson and Vietnam. The question becomes: where do we hide the president?"

Bush could run, but he can't now hide. Rove showed Bush how to win elections, but he couldn't show him how to govern. For the next year and a half he may need more than a feather pillow to get him to sleep.

g.younge@theguardian.com