"It's a source of income for me," Cleland said of the Monday joint appearance, sponsored by an insurance trade group, for which he said he was paid $15,000. (Rove's speeches typically bring $40,000.)

Going up against Rove, Cleland said, "is like going up against the devil himself."

It can pay to be the devil himself, or at least thought of that way. "There is an incredible amount of interest in what Karl Rove has to say," said Howard Wolfson, a senior adviser to Sen. Hillary Rodham Clinton's presidential campaign, who appears regularly with Rove on Fox News.

Wolfson said he was amazed by how often Democrats asked him what Rove was like off the air. "When I say he's nice, people look at me like I'm nuts," he said.

Rove declined to be interviewed for this article but engaged somewhat by e-mail. He said little on the record, ignored some questions and was dismissive of others.

"Look," he wrote, "I don't mean to be rude but I have so much on my plate that my brain explodes when you ask questions like how much of my time I spend on each of my activities or how did I apply skills to my new chapter, et cetera. I can answer simple questions of fact, but I am stretched through the election."

But it clearly delights him, for instance, that Sen. John Kerry of Massachusetts went on about "the smears of Karl Rove" during his speech at the Democratic National Convention in August. Rove helpfully pasted a passage from Kerry's speech on Rove.com, under the headline "The Losers Have Spoken."

Two top McCain campaign aides, Steve Schmidt and Nicolle Wallace, worked closely with Rove in the White House and are commonly referred to as "Rove proteges," a designation that both dispute. McCain's top advisers shudder at the perception that Rove is calling shots for their campaign — in part because his reputation is toxic among many swing voters, and perhaps the best-known victim of "Rovian" hardball tactics was McCain himself in the 2000 Republican primary campaign.

People close to Rove said he was determined to leave his mark on this race through public channels. He prepares diligently for his television appearances and sprinkles his commentaries with the kind of wonkery that goes well beyond the repertoire of most talking heads. ("The Urban Institute and the Brookings Institutions did a study of the Obama tax plan," Rove said on Fox's "Hannity and Colmes" after Tuesday's debate. "The top 5 percent will pay $131 billion more in taxes.")