NY Times :
Former Senator Fred Thompson, who now plays a district attorney on "Law & Order," told Fox News today that he'll make a decision in the coming months about whether to jump into the field of Republican candidates vying for the 2008 presidential nomination.
"I'm going to wait and see what happens," Mr. Thompson said. "I want to see my colleagues on the campaign trial, what they say, what they emphasize, whether they can carry the ball next November." [..]
Mr. Thompson, who served as a senator from Tennessee from 1994 until 2003, said he was leaving the door open for a return to the political stage.
Thompson has had a very colorful career in Washington. From Wikipedia:
He was the campaign manager for Senator Howard Baker's successful re-election campaign in 1972, which led to a close personal friendship with Baker, and he served as co-chief counsel to the Senate Watergate Committee in its investigation of the Watergate scandal, (1973-1974). He was responsible for Baker's asking one of the questions that is said to have led directly to the downfall of President Richard Nixon-"What did the President know, and when did he know it?" Also, Thompson's voice has become immortalized in recordings of the Watergate proceedings, asking the key question, "Mr. Butterfield, are you aware of the installation of any listening devices in the Oval Office of the President?"
In 1977, Thompson took on a Tennessee Parole Board case that ultimately toppled Tennessee Governor Ray Blanton from power on charges of selling pardons. The scandal became the subject of a book and a movie titled Marie (1985) in which Thompson played himself, supposedly because the producers were unable to find a professional actor who could play him plausibly.