Public TV's Jim Lehrer, a veteran presidential debate moderator who handled last year's first clash between President Obama and Republican Mitt Romney, said moderator fact-checking like Candy Crowley's abrupt rebuke of Romney in the second debate is a fatal error that ruins the historic events--and should always be avoided.

"As a general premise, I believe debate moderators are not there as fact-checkers," said Lehrer, host of NewsHour on PBS. "They are there to facilitate the exchange between the candidates. If there is going to be any fact-checking done, it should be done by the other person."

While saying he is not specifically critical of CNN's Crowley, Lehrer essentially called her out for breaking the flow of the debate, which was considered a turning point for Obama who lost the first debate. Critics have said that Crowley went to bat for Obama, endorsing his false claim that he had called the attack on the U.S. facility in Benghazi, Libya an "act of terror."

Lehrer addressed the issue during a post-election speech at the Clinton School of Public Service at the University of Arkansas. At first he pretended to duck a question about Crowley, then spoke passionately against debate fact-checking for three-and-a-half minutes.

He said he has had to check his journalistic tendencies to fact-check and question candidates during the debate. "If a moderator interferes in the flow, it interferes with the flow and I think that in terms of priorities, the flow is more important than stepping in and saying, OK, clarifying something, or correcting something. I'm not criticizing Candy Crowley or anything else, I'm just saying that is my general view of it," said Lehrer.

Instead, he said the moderator should let the show go on, and leave corrections to campaigns, reporters and voters. "See the debate as a presentation and a confrontation, if you will, between the two candidates and then all the stuff that flows from that can then be sorted out after that," he explained.

The bottom line for debate moderators, he said: "You have to put a different cloak on, over your mind and your mouth and everything else. When you moderate something, you are a moderator, you are not functioning in a journalistic capacity. You are functioning as somebody who is involved in a crucial event and your job is to moderate a discussion and to moderate it, not to interview, not do simultaneous, or back-to-back simultaneously one-on-one interviews with candidates which some people go to these things thinking that's what they should do. To me thats not what should be done."

The question about Crowley occurs about at 46 minutes into Lehrer's address.

To recap, below is the transcript of the Obama, Crowley, Romney clash at the October 16 debate:

ROMNEY: I -- I think interesting the president just said something which -- which is that on the day after the attack he went into the Rose Garden and said that this was an act of terror.

OBAMA: That's what I said.

ROMNEY: You said in the Rose Garden the day after the attack, it was an act of terror.

It was not a spontaneous demonstration, is that what you're saying?

OBAMA: Please proceed governor.

ROMNEY: I want to make sure we get that for the record because it took the president 14 days before he called the attack in Benghazi an act of terror.

OBAMA: Get the transcript.

CROWLEY: It -- it -- it -- he did in fact, sir. So let me -- let me call it an act of terror...

OBAMA: Can you say that a little louder, Candy?

CROWLEY: He -- he did call it an act of terror. It did as well take -- it did as well take two weeks or so for the whole idea there being a riot out there about this tape to come out. You are correct about that.