“I’ve never even met the man, never spoken to him,” Limbaugh said. “I’m sure there are things about him I’d like if we meet. This isn’t personal.” He then delivered a litany of the presumptive nominee’s personal failings  too old, too intense, too opportunistic, too liberal. But, he assured me, he would be with McCain in the fall. “It’s like the Super Bowl,” he told me. “If your team isn’t in it, you root for the team you hate less. That’s McCain.”

It already seemed, when I made my visit, that McCain’s opponent might well be Senator Obama, and I was curious to know how Limbaugh planned to take on America’s first African-American major-party nominee. “I’ll approach Obama with fearless honesty,” said Limbaugh, who speaks of himself in heroic terms on air and off. “He’s a liberal. I oppose liberals. That’s all that’s involved here.”

I asked if he had any specific tactics in mind.

“I haven’t yet figured that out exactly,” he said. “You know, I’ve had a problem with substance abuse. I don’t deal with the future anymore. I take things one day at a time.”

In this case, it took two. I was back in New York, listening to the radio, when I heard Limbaugh say: “Ladies and gentlemen, I had a conversation with a friend Wednesday afternoon after the program, and he said, ‘Nobody’s criticizing Obama. How are you going to do this? How are you going to handle criticizing the first black American to run for president?’ I said: ‘I’m going to do it the way I always do it. First, at the top of the list, I’m going to do it fearlessly. I’m not going to bow to political correctness. I’m going to do it with humor. I’m going to focus on the issues. I’m going to react to what he says. Simple. I’m going to do it just like it were any other case  he’s a man, right? He’s a liberal. How do I criticize liberals? I criticize them.’ But I have devised, ladies and gentlemen, an even more creative way of criticizing Obama. I have, just this morning, named a new position here on the staff that is the Official Obama Criticizer. The E.I.B. Network now has an Official Obama Criticizer. He is Bo Snerdly.”

Snerdly introduced himself as an “African-American-in-good-standing-and-certified-black-enough-to-criticize-Obama guy,” and declared that he was speaking, “on behalf of our E.I.B. brothers and sisters in the hood.” The bit was typical Limbaugh  confrontational, deliberately insensitive and funny. It was also a declaration of independence. Whatever special courtesies John McCain might plan to extend to Barack Obama, Limbaugh is going to conduct his air war, as he always has, by his own rules of engagement.

ON AUG. 1, LIMBAUGH WILL CELEBRATE the 20th anniversary of his national radio program. At 57, he is an American icon, although his fans and critics don’t agree on precisely what he is iconic for. I’ve heard him compared to Mark Twain and Jackie Gleason, the Founding Fathers and Father Coughlin. Serious people have called him a serial liar and a moral philosopher, a partisan hack and a public intellectual, nothing more than a radio windbag and nothing less than the heart of the Republican Party.

One thing is certain: Limbaugh has been a partisan force for two decades. In 1994, he was so influential in the Republican Congressional landslide that the grateful winners made him an honorary member of the G.O.P. freshman class. He moved not only voters, but the party itself. “Rush talked about the ‘Contract With America’ before there was a ‘Contract With America,’ ” Karl Rove told me. “He helped set the agenda.”