Weekly Standard Editor Bill Kristol said Wednesday that he still fears Donald Trump could win the White House in November because 2016 is shaping up to be a "change election."

"The only reason he could win is this: It's a change election," Kristol said on MSNBC.

"I was in the first Bush White House in '92," he explained. "I think President George H.W. Bush did a pretty good job, Bill Clinton was a very flawed challenger ... and if the people want change, they're willing to make a lot of excuses for the challenger."

Kristol has been one of Trump's most vocal conservative critics, and has worked for months to find an alternative Republican candidate. His Weekly Standard is owned by the same company as the Washington Examiner.

He said another factor that could still help Trump is more trouble on Hillary Clinton's side.

"Yeah, it's a very unusual and fluid year, stuff could come out about Hillary Clinton," he said.

Kristol said Clinton's lead in recent polls "should hold" based on how past elections have played out. But he added, "I think people are being too complacent about that."

"He is who he is, he believes in who he is, he thinks he's shown the pundits are wrong once, he's going to show them again, and you know, I'm not 100 percent confident he's not, incidentally," he said of Trump.