Mark Smith, a reporter for The Associated Press who is president of the White House Correspondents' Association, acknowledges that he had not seen much of Stephen Colbert on Comedy Central before he booked him as the main entertainment for the association's annual black-tie dinner on Saturday night. But he says he knew enough about Mr. Colbert — "He not only skewers politicians, he skewers those of us in the media" — to expect that he would cause some good-natured discomfort among the 2,600 guests, many of them politicians and reporters.

What Mr. Smith did not anticipate, he said, was that Mr. Colbert's nearly 20-minute address would become one of the most hotly debated topics in the politically charged blogosphere. Mr. Colbert delivered his remarks in character as the Bill O'Reillyesque commentator he plays on "The Colbert Report," although this time his principal foil, President Bush, was just a few feet away.

"There was nothing he said where I would have leapt up to say, 'Stop,' " said Mr. Smith, who introduced Mr. Colbert and sat near him on the dais. "I thought he was very funny," Mr. Smith added, though there was hardly consensus on that point yesterday.

At issue was a heavily nuanced, often ironic performance by Mr. Colbert, who got in many licks at the president — on the invasion of Iraq, on the administration's penchant for secrecy, on domestic eavesdropping — with lines that sounded supportive of Mr. Bush but were quickly revealed to be anything but. And all this after Mr. Colbert tried, at the outset, to soften up the president by mocking his intelligence, saying that he and Mr. Bush were "not so different," by which he meant, he explained, "we're not brainiacs on the nerd patrol."