(CNN) -- The morning after a debate gaffe that many political watchers say will go down in modern political history, Gov. Rick Perry of Texas said his "brain freeze" shows that he is not "the slickest politician" among the field of Republican presidential hopefuls.
His campaign, meanwhile, sought to do some fundraising off the gaffe, encouraging supporters to send $5 for every government agency they "would like to forget."
Perry's team said he will appear on CBS' "The Late Show with David Letterman" to present the "Top Ten List" Thursday night.
During the debate in Rochester, Michigan, on Wednesday night, Perry said he would eliminate three federal agencies if elected president, but he was able to name only two of them.
That produced a painful period of more than 50 seconds during which he tried in vain to remember the third federal agency. It ended only after Perry conceded that he could not remember it -- even after appearing to consult his notes.
"Oops," he said.
Perry addressed the gaffe Thursday on CNN's "American Morning."
"I bet there are a lot of Americans out there that would like to forget some agencies of government, too," Perry quipped, smiling through the interview.
Operatives from the left and the right slammed the moment as a potential sign of Perry's campaign imploding. The New York Times quoted Mark McKinnon, an aide to former President George W. Bush, as calling the moment the "human equivalent of shuttle Challenger."
Speaking to CNN's Christine Romans on Thursday, Perry said, "we need substance more than we need style" and tried to turn the incident into an attack on President Barack Obama.
When Romans said that the president has to be "debater in chief," Perry responded, "We've got a debater in chief right now. And you've got to ask yourself: How's that working out for America?"
Another part of Perry's effort to move on from the gaffe: Front and center on his website Thursday was a poll asking, "What part of the federal government would you like to forget about the most?" Visitors can choose from one of 10 choices or send their suggestions to "firstname.lastname@example.org."
His campaign sent out a note to supporters saying, "We've all had human moments."
The note from "Team Perry" points out that Obama, at a campaign stop during the 2008 election, referred to having visited "57 states."
"Ronald Reagan got lost somewhere on the Pacific Highway in an answer to a debate question," the note adds. "Gerald Ford ate a tamale without removing the husk. And tonight Rick Perry forgot the third agency he wants to eliminate. Just goes to show there are too damn many federal agencies."
In a 1984 debate against Walter Mondale, then-President Reagan delivered a closing statement that was widely viewed as rambling. He began by describing a day he had driven down the California coast. Reagan had to be cut off by the moderator. Ford, in 1976, was meeting voters in Texas when he bit into a tamale. Unaware of how to eat it, he did not first remove the husk.
The Perry campaign's note asks supporters to "throw in a $5 contribution for every agency you would like to forget."
At the debate, Perry was facing Texas Rep. Ron Paul when he started to answer the question.
"I will tell you, it is three agencies of government when I get there that are gone," Perry said. "Commerce, Education, and the -- what's the third one there? Let's see. OK. Commerce, Education, and the ... "
"EPA?" Mitt Romney offered.
"EPA, there you go," Perry said.
When pressed by moderator John Harwood if the Environmental Protection Agency was indeed the third agency he proposes shuttering, Perry admitted that it wasn't. He then attempted again to remember the details from his plan.
"The third agency of government I would -- I would do away with Education, the Commerce, and, let's see. I can't. The third one, I can't. Sorry. Oops."
Several minutes later, Perry clarified that the agency he was trying to remember was the Department of Energy.
Perry was already saddled with a series of lackluster debate performances and is down in the polls.
On Twitter, reaction was swift.
"Perry collapses. Cannot remember a list of three federal government departments he wants to abolish past the first two. Seriously. And then he says 'oops.' He has all but disappeared inside his suit in this debate and is now basically done," conservative blogger Andrew Sullivan tweeted.
CNN Senior Political Analyst David Gergen wrote, "Was that the most embarrassing moment of the campaign --#RickPerry unable to remember the 3rd cabinet dept he would eliminate?"
Dana Loesch, a conservative radio host and CNN contributor, asked, "How can Perry recover from that?"
Democratic strategist and CNN contributor Roland Martin exclaimed, "Damn, he actually forgot the third federal agency he would get rid of! That is THE MOST EMBARRASSING moment of any debate I've seen!"
Appearing in the spin room after the debate, Perry tried to make light of the gaffe.
"I'm sure glad I had my boots on," he said, "because I sure stepped in it out there."
CNN Political Reporter Peter Hamby contributed to this report.