Whatever history makes of Karl Rove’s role in the White House, his legacy as a political strategist can be measured in a presidential campaign that has already begun without him. A look at the roster of every Republican presidential candidate finds people who have worked with him, and they have brought some of his methods to this race.

But Mr. Rove leaves the White House anything but victorious. His legendary reputation, forged by steering George W. Bush to two arguably unlikely victories, was seriously diminished by the Republican defeats of 2006. He is blamed in Republican circles for many of the political problems President Bush has suffered in a difficult second term — problems that occurred as Mr. Rove expanded his writ and tried his hand at policy.

Those setbacks have contributed to a partywide sense of foreboding about keeping the White House in Republican hands.

“He gets more credit and more blame than he deserves,” said John Weaver, a former senior adviser to Senator John McCain, Republican of Arizona, who has had a long history of fighting with and working with Mr. Rove. “At the end of the day, he was the head coach of the political team that won the equivalent of the Super Bowl two times in a row. But other things he did are more subjective: the kind of campaigns that were run and their impact on governing.”

Certainly, Mr. Rove has to a considerable extent changed the way presidential politics are played. Modeled on his example, campaigns have become more disciplined in driving simple, often negative messages. They begin in trying to identify the vulnerabilities of potential opponents, and they do extensive negative research as they prepare to exploit those vulnerabilities early and often.

They seek to work out long-term, month-by-month game plans and stick with them, even in difficult times. And they methodically use marketing and other data to identify potential supporters and get them to the polls with an efficiency that had never been seen before, something Mr. Rove pushed along with his close ally, Ken Mehlman, the former Republican National Committee chairman.

“The Rove model was so impressive that the front-runner for the nomination is following the blueprint,” said Mark McKinnon, who worked with Mr. Rove in 2004 and is now advising Mr. McCain’s presidential campaign. “It is almost the Powell doctrine of politics: you just hit them with everything you got, everywhere and at the same time.” The front-runner he was referring to, Mr. McKinnon said, is a Democrat, Senator Hillary Rodham Clinton.

But whether Mr. Rove would be welcome to join any of the Republican presidential campaigns was a question met with silence when it was posed to campaign aides on Monday. If some of Mr. Rove’s signature achievements have been eagerly imitated, others — including an emphasis on turning out Republican base voters by focusing on polarizing issues like same-sex marriage — have been discredited by polls suggesting that the base is shrinking in Mr. Bush’s second term.

Not incidentally, Mr. Rove also leaves the White House as an extraordinarily polarizing figure, as was evident on Monday in the way some conservative bloggers joined Democratic ones in expressing delight at his departure.

Even some Republicans have said Mr. Rove’s decision to assume more authority over policy and legislation after helping Mr. Bush win his second term may have been a mistake.

The prowess Mr. Rove displayed in running a campaign was not in evidence as he tried to oversee the White House’s difficult dealings with Congress, producing two years with few legislative gains. Mr. Rove’s strategy of appealing first to the Republican base, which helped Mr. Bush win key victories in pivotal states like Ohio in the 2000 and 2004 elections, did not work in a Congress that required cooperation and negotiation with friend and foe.

Mr. Rove’s campaign skills were less in dispute.

“The biggest thing he has done campaign-wise is message discipline: focusing relentlessly on one thing and driving it home,” said Alex Castellanos, a senior adviser to the presidential campaign of Mitt Romney, the former Massachusetts governor.

Terry Nelson, an associate of Mr. Rove who managed Mr. McCain’s campaign until he left in a shake-up this summer, noted that the number of officials who came out of the Rove-Mehlman shop and were working in 2008 campaigns suggested Mr. Rove’s continuing influence.

The demand for veterans of the 2004 campaign reflects a hunger “for people who are disciplined and focused to do what is necessary to win a campaign,” Mr. Nelson said.

In an interview late Monday, Mr. Rove said the list of voters he developed with Mr. Mehlman would help the party win elections for years. Having predicted until the final hours in 2006 that Republicans would keep Congress, Mr. Rove remained ever the optimist, predicting that Republicans would keep the White House next year.

But he said it was a “mistaken impression” that “this is all about playing to the base; that supposedly the success of the two campaigns have been that the president played to the base of the Republican Party. Completely inaccurate.”

To a certain extent, Republicans said, Mr. Rove will have some influence with the major Republican presidential candidates simply because he is friends with, or has worked with, so many people who are working at the senior levels of the campaigns of Rudolph W. Giuliani, Mr. McCain and Mr. Romney, to name a few. He talks with them frequently and has made it known, associates said, that he is ready to offer advice when asked.

Mr. Rove said Monday that he did not anticipate “taking any formal role” in any campaign.

But it is hard to imagine him staying out if his services are requested. This election may be Mr. Rove’s last chance to salvage a reputation that was damaged in 2006. He surely recognizes that being identified with a successful effort to win back Congress and to keep the White House could restore at least some of the luster to a man who was so long described in Washington as a political genius.

Yet it has become increasingly clear that the Republican candidates for 2008 are not competing for either the mantle of Mr. Bush or the services of his master strategist.

There probably was no better evidence of this than in Iowa over the weekend, where the straw poll in Ames was a gathering point for some of the most committed Republicans in the country. At the same contest in 1999, Mr. Rove showed his political skills to the country, steering Mr. Bush to a victory in a nonbinding poll that nevertheless cemented his position as his party’s prohibitive favorite.

This year, Mr. Bush’s name was barely mentioned, much less Mr. Rove’s, and the winner of the contest, Mr. Romney, offered a grim verdict on these past seven years in Washington — and arguably on Mr. Rove himself.

“If there has ever been a time that we needed to see change in Washington it is now,” Mr. Romney told Iowa Republicans. The line drew some of his strongest applause of the day.