For four years, the White House believed it would need an army to install President Bush's choices on the Supreme Court, and it set about building one. Political committees were formed, millions of dollars raised, coalitions of allied groups assembled, action plans mapped out, media campaigns scripted.

Yet now, as the president struggles to sell the nomination of Harriet Miers, much of Bush's army is refusing to leave the barracks -- and part of it is even going over to the insurgency.

The apparatus constructed largely by Bush strategist Karl Rove and deployed effectively on behalf of recently confirmed Chief Justice John G. Roberts Jr. has splintered over Miers and broken free from its commander. Conservative organizations that generated millions of e-mail messages on behalf of Roberts have silenced their servers. Airwaves that sizzled with commercials demanding a Senate vote just weeks ago carry no such ads into living rooms now. The followers of these groups are not flooding their senators with supportive telephone calls and letters.

The split seems to be evolving into one of the most profound schisms in years within a conservative movement whose unity has buoyed Bush through his most difficult moments and earned the envy of the political left. While conservative groups have disagreed over policies in the past, rarely have they turned against a president so normally aligned with them on such a central, legacy-building priority.

"I don't know of anybody that is right now planning to go all out, whereas I know that had a different kind of nominee been selected, that people were prepared to go full tilt," said Paul M. Weyrich, founder of the Free Congress Foundation, who so far has declined to support Miers.

"They are still fully armed, loaded for bear, but they're not about to fire on behalf of someone whose qualifications they're still questioning," added Janet M. LaRue, chief counsel of Concerned Women for America, another group that has withheld its backing.

During the Roberts confirmation process, LaRue helped mobilize her organization's 500,000 members to press the Senate. "We were doing stuff every day -- press releases every day, sometimes a couple a day, e-alerts every day or every other day," she said. "Now all I can do is explain why we haven't. . . . Right now you've got hardly anything being done for Miers. It's so noticeably silent."

So silent, in fact, that the White House is trying to step in to do some of the salesmanship it otherwise might have preferred to leave to outside political groups. Bush hosted half a dozen former Texas Supreme Court justices in the Oval Office yesterday to highlight their support of Miers, the sort of validation event he did not need personally to mount on behalf of Roberts.

"They're here to send a message here in Washington that the person I picked to take Sandra Day O'Connor's place is not only a person of high character and of integrity but a person who can get the job done," Bush said, flanked by the ex-judges. The president added, "She's impressed these folks. They know her well. They know that she'll bring excellence to the bench."

The White House hoped the appearance would help it refocus attention on Miers's qualifications and away from issues such as her religion and position on abortion. But it found that such topics continued to assert themselves amid a report from a Wall Street Journal columnist that two other judges who are close to Miers told conservative activists on a conference call the day she was nominated that they believed she would vote to overturn Roe v. Wade, the 1973 ruling that legalized abortion nationwide.

Such disjointed messages are easier to avoid with an integrated campaign backing a president, and Bush advisers rue the fragmenting of the team they put together. Through intermediaries and more conference calls and e-mails, White House officials are trying to lobby estranged supporters and reassemble the coalition.

But without their normal allies, White House officials are focusing on senators themselves. While some Republican senators have expressed qualms about Miers, the White House is counting on its ability to hold its caucus together. Bush allies in New Hampshire and Iowa are starting to pressure Republicans who want to run for president in 2008, such as Sen. Sam Brownback (Kan.), to back Miers. And yesterday's Oval Office event was intended to quash talk that Bush might withdraw the nomination, officials said.

"If there is a third-party fight out there, you want your people fighting, no doubt about that," said a White House official who spoke on the condition of anonymity, citing internal policy. But "the most important people to learn who she is obviously are the senators who will vote on her."

If the White House succeeds in pushing Miers through the Senate without the help of its allied groups, their influence may be reduced. At the same time, though, the White House could be left with a festering problem within its own party.

The broader nature of the split becomes clearer with each conservative declaration of independence from the Bush White House. David Keene, chairman of the American Conservative Union, wrote yesterday that many of his friends "swallowed policies" they opposed out of loyalty to Bush.

"We've been there for him because we've considered ourselves part of his team," Keene wrote in an essay printed in the newspaper the Hill and e-mailed to fellow conservatives. "No more. From now on, this administration will find it difficult to muster support on the right without explaining why it should be forthcoming. The days of the blank check have ended."

Not all conservative groups have abandoned Bush. Progress for America, a group with close ties to Rove, unveiled a $10,000 Internet ad yesterday and has a Web site devoted to Miers. But it has not devoted as much money yet to her confirmation as it did to Roberts's. Immediately after his nomination in July, Progress for America launched a $1 million television buy supporting him. The group spent just $300,000 for ads in the days before and after Miers's nomination, with about half of those spots congratulating Roberts on his confirmation without mentioning Miers.

The group's spokeswoman, Jessica Boulanger, said that, overall, Progress for America has spent $500,000 supporting Miers in the two weeks since her nomination; it spent something less than $9 million over the 10-week Roberts campaign. "We plan to have a similar effort on behalf of the Miers nomination," Boulanger said.

Jay Sekulow, chief counsel at the American Center for Law and Justice and a key conservative adviser to the White House, said the outside campaign has started slowly but will grow much more intense when the Senate opens hearings. "A lot of the religious conservative groups have lined up pretty well," he said. "Some of the other conservative groups have been a little late to this one."

Late or perhaps not coming at all. Some conservatives have even begun raising money or circulating petitions in outright opposition to Miers. As Manuel A. Miranda, former nominations counsel to Senate Majority Leader Bill Frist (R-Tenn.), put it in an e-mail to colleagues, "Two weeks later, the nomination's friends have been its worst enemies."