Former Tennessee Sen. Fred Thompson is facing increased calls to get into the 2008 GOP nomination race.
Sources told FOX News that Thompson, 62, now one of the stars of the popular NBC prime time series "Law & Order," has not ruled out a presidential bid, and has authorized advisers and supporters to continue to gauge support.
Advisers are holding regular strategy sessions, investigating fundraising avenues and private polling to measure enthusiasm. Perhaps pre-eminent among a number of prominent Thompson backers working behind the scenes is former Senate Majority Leader Howard Baker.
Baker has been a mentor to Thompson since before the Senate's Watergate hearings, for which Baker hired Thompson as majority counsel and for which Thompson earned fame for having Baker ask the key question that led to President Richard Nixon's downfall: "What did the president know and when did he know it?"
Baker ran for president himself in 1980. Thompson eyed the White House in the 1990s.
While Thompson, who also helped raise money and advise I. Lewis "Scooter" Libby's legal defense fund, continues to mull a bid, sources said he has been inundated with calls from GOP donors and supporters urging him to run.
Thompson has a solid and consistently conservative voting record that his supporters said makes a stark contrast to Republican frontrunners Rudy Giuliani, John McCain and Mitt Romney.
This week, he told radio news host Mark Levin that he would have something to say about his plans, but not yet.
As Thompson considers his next step, Republican Sen. Chuck Hagel has scheduled a news conference for Monday at the University of Nebraska. Speculation is increasing that during Monday's press conference, Hagel will play the same card used by former House Speaker Newt Gingrich card, who has said he's interested but hasn't made a decision.
Hagel has three options during his announcement. He could announce that he's retiring from the Senate, he is running for re-election to his Senate seat in 2008 or that he will run for president.
FOX News' Carl Cameron contributed to this report.