Brian Williams, who anchored the NBC Nightly News from Washington last night, is expected to leave for Mississippi today, as is CBS anchorwoman Katie Couric, who last night anchored from New York.

ABC's coverage of the debate will be anchored by Diane Sawyer, Charles Gibson and George Stephanopoulos, but they will be doing so from New York. Correspondents for ABC News have been in Oxford since Wednesday.

CNN, which has provided some of the most extensive coverage of the primaries and related debates, has the largest cable contingent in Oxford. It includes CNN correspondents Dana Bash, Candy Crowley, Ed Henry, Suzanne Malveaux and Jessica Yellin and senior political analyst Bill Schneider. Wolf Blitzer, Anderson Cooper and Campbell Brown will anchor from New York, with senior correspondent John King providing analysis.

In an interview with the Baltimore Sun earlier this week, Lehrer said his primary goal as moderator was to serve as a "catalyst" for a discussion between the candidates. And while he declined to discuss the specifics of the questions he had drafted, he did not rule out the possibility that he would go beyond the suggested parameters of national security and foreign affair to query the candidates on the nation's economic crisis.

"It's about the candidates. It isn't about the moderator," he said. "It isn't about pressing the candidates. It's to make it possible for the people who are running for president to exchange their ideas rather than to bounce off mine."

The 74-year-old anchorman, who moderated his first presidential debate in 1988 between Michael Dukakis and George H.W. Bush, stressed the need for him to be seen as impartial.

"Fairness and the appearance of fairness are critical, because everything must appear to be absolutely straight and driven by the views of these people who want to be president rather than by some agenda that the moderator may have," said the dean of American news anchors. "This is not me saying, 'Hey, I want to reveal this' or 'I want to do that.' This is a different purpose."

Lehrer described the format for tonight's scheduled debate as "wide open" and "freewheeling."

"It's the first time that things have been really loosened up - where the candidates can direct questions to each other," he said. "There will be a question that goes to both of them, and they'll have two minutes each to answer. But then, there's another five minutes that is wide open afterward - for them to speak to each other, or me, or for me, the moderator, to ask follow-ups, before going to another question. And there will be nine segments like that over almost 90 minutes."

As to the questions he will ask, Lehrer said: "I have drafted them all - and I've shared them with nobody, cleared them with nobody."

Read the full interview with Lehrer including comments from the newsman on his health here.

And if the debate is held, I will be blogging right after here.