By a twist of fate, Hillary Clinton, also a lawyer, was also in the room working for Nixon's impeachment.

Nearly 34 years later, the two lawyers, one a Democrat, the other a Republican, have every chance of being their party's nominees for the 2008 US presidential election.

For the past three decades, the Republican has been making his languid way through American life, first as a young lawyer, then as senator from Tennessee and finally, when he grew bored with that, as a Hollywood actor who liked to play the straighttalking, tough-as-nails wise southerner. It didn't hurt that he was 6'4" and delighted in his good-ol'-boy reputation as a ladies' man. Brusque to the point of rudeness, Thompson's most natural expression is a scowl.

As the US goes through a period of deep insecurity, with defeat looming in Iraq and the body count of young working-class Americans rising, the prospect of another reassuring B-list actor taking over the presidency is apparently deeply reassuring. This is hardly surprising given that the average person spends up to four hours a day slouched in a La-Z-Boy chair watching TV.

Indeed Thompson's biggest asset may be that . . . just like Ronald Reagan before him . . . viewers (make that voters) already feel they know how he would behave as Leader of the Free World. He is best known as the tough-talking New York district attorney Arthur Branch in the TV series Law & Order. He has appeared in many Hollywood movies, often cast as the person running the show, whether as president of the US, White House chief of staff or head of the CIA.

But the fact remains that Thompson is a creature of the TV age . . . a man for whom Marshall McLuhan's axiom that "the medium is the message" might have been written. From his Watergate days, when he cleverly asked a question that was already common knowledge inside the inquiry . . . thereby showing Republicans in a favourable light . . . Thompson has understood the power of the media to influence Americans: "Until then, I had not fully appreciated the power of television or the fact that anyone who gets sufficient television exposure . . . is an overnight celebrity, " he said later.

When 20 years later he entered politics and ran for the Senate in Tennessee, Thompson revealed how he used TV as the driving force in the campaign: "The camera doesn't lie. It looks straight into your soul. I'm the only one in this race who has known it. And it's now paying off."

For Republican Party candidates who are busy criss-crossing the country and staking out positions that appeal to their most conservative voters, Thompson, who has yet to announce his candidacy, is the elephant in the room. Although he has yet to raise any money in a contest that demands tens of millions of dollars from every candidate . . . it's spent almost entirely getting 30-second spots on TV . . . the prospect of his entering the race, as soon as this week, is already causing a political earthquake.

He is racing up in the polls, leaving alreadydeclared candidates with war chests of millions of dollars in the dust. Twenty-four per cent of Republican voters support both Rudy Giuliani and Thompson according to the latest poll. Last week, Thompson was trailing Giuliani by just 6% according to a poll of 633 likely Republican primary voters.

Life has really started to imitate art. Journalists describing his character tells us that in Die Hard II, as head of Washington Dulles airport, "he actually looks physically pained when terrorists force a jetload of passengers to crash and burn on the runway". It will be reassuring to know that Thompson has this talent for empathy, should he ever make it to the White House and get his finger on the nuclear button.