David Frum, the Canadian-born conservative commentator who has been harshly critical of the Republican battle plan against U.S. President Barack Obama's health-care overhaul, is unapologetic after being fired by a right-wing think-tank.

"I'm going to remain a conservative, whether they want me or not," Frum told The Canadian Press on Thursday night after his ouster from the American Enterprise Institute, adding he was saddened by the turn of events.

"In a democracy there are competing teams, and each team has to bring its best game to the table. ... Health-care reform is here to stay, it isn't going to be repealed, and it was within our grasp to help formulate it and we failed to do so. Instead, we decided to do whatever we could to make Democrats look wicked and evil."

On Sunday, Frum wrote on his website, FrumForum, that health-care reform had been a debacle for Republicans, saying they had "suffered their most crushing legislative defeat since the 1960s."

"A huge part of the blame for today's disaster attaches to conservatives and Republicans ourselves," he wrote.

"At the beginning of this process we made a strategic decision: unlike, say, Democrats in 2001 when President Bush proposed his first tax cut, we would make no deal with the administration. No negotiations, no compromise, nothing."

While Republicans predicted months ago that health-care reform would be Obama's "Waterloo," Frum wrote: "It's Waterloo all right: ours."

Attacked by Journal

The White House press secretary gleefully tweeted Frum's blog post on Sunday. Frum's ouster from the American Enterprise Institute came a day after the Wall Street Journal attacked Frum, a former speechwriter for George W. Bush and son of the late CBC broadcaster Barbara Frum.

"Mr. Frum now makes his living as the media's go-to basher of fellow Republicans," the Journal wrote. "But he's peddling bad revisionist history that would have been even worse politics."

Frum said while he was sad about the dismissal, he had been in a similar situation before, albeit north of the border — at odds with the conservative movement for an unpopular but ultimately correct stance he took.

"Back in '95, I said that PCs [Progressive Conservatives] and Reformers were going to have to come together and to work together, and I didn't say that because I was a liberal. History proved me right," he said.

Frum, now a U.S. citizen, made a name for himself in Washington for penning Bush's "axis of evil" remarks in the aftermath of Sept. 11, 2001. In recent months, he has angered some U.S. conservatives for his criticism of Rush Limbaugh and Sarah Palin.