The commission ruled out picking one of the top three network news anchors, knowing how the other two might react. Mr. Lehrer had sworn he would never moderate a presidential debate again, perhaps in part because of the criticism he received in 2000 that he was not aggressive enough, prompting him to scoff, “If somebody wants to be entertained, they ought to go to the circus.”

When commission members asked if he would change his mind, he initially answered with a Shermanesque statement: “If drafted, I will not run; if nominated, I will not accept; if elected, I will not serve.”

But he was eventually persuaded, he said, by a new debate format: six distinct 15-minute segments, with candidates getting two minutes to respond to questions, with the remaining time left for a deeper exploration of a topic.

“He sniffed around when they got the new format and became interested again,” said one television official who, like the others involved in the process, would not speak for the record because the discussions were private. “There is always lobbying that goes on, but people were surprised that this is who they ended up with.”

Fox News, which is the only independent television network that has not been selected to have one of its anchors host a debate, made an aggressive push this year. The commission sent signals that the network was in strong contention, people familiar with the process said, but that changed in the last month. The Obama campaign raised questions about the network because of its conservative leanings. The Romney campaign objected to MSNBC because of its liberal bent and threatened to boycott if one of its anchors was selected.

Mr. Schieffer, known as “Schieff” to several members of the commission, was seen by participants as a likely moderator from the beginning. Wolf Blitzer of CNN was believed to be a leading contender, but a desire for diversity elevated Ms. Crowley, after Mr. Lehrer and Mr. Schieffer were already in place, according to people familiar with the discussions.

On Friday, Rush Limbaugh railed against Ms. Crowley (“a far, far left-wing Democrat momma”) and Mr. Schieffer (“a far, far left-wing Democrat and dinosaur”). He called Ms. Raddatz and Mr. Lehrer “far, far left” as well. More surprising was the reaction at PBS’s NewsHour, Mr. Lehrer’s home for more than 35 years until his retirement last year. The morning editorial meeting was under way on Monday when The Drudge Report revealed the names of the four moderators. Gwen Ifill and Judy Woodruff, the leaders of the program’s political coverage, were stunned to see the names.

In the suddenly gloomy meeting, some wondered if the list was legitimate. Others murmured that the selection of Mr. Lehrer was a setback for the “NewsHour,” which has been trying to show off younger stars like Ms. Ifill. Ms. Ifill, in particular, was livid, according to several people present. “I was indeed disappointed,” she confirmed Friday.