Al Gore - a man widely believed to have been groomed for the US presidency from birth - has announced that he does not intend to challenge George W Bush for a second time.

His announcement came earlier than expected and took many by surprise.

In recent months, two big policy speeches in the space of two weeks sent a clear signal that he had developed an appetite for the fight.

First, he broke ranks with his fellow Democrats in September by openly criticising the president's determination to attack Iraq.

Future world leaders do not play the violin Al Gore's mother during his childhood

He accused Mr Bush of losing sight of the goal of hunting down the perpetrators of the 11 September attacks and of jumping "from one unfinished task to another".

In a second speech, Al Gore focused on the faltering US economy, warning of a "global crisis of confidence" in America's economic leadership.

Put together, they sounded like the words of a man trying to stake out his political territory for the battle ahead.

There had already been what had been interpreted as clues - it had not gone unnoticed that he had shaved off a beard grown in the aftermath of his defeat in the 2000 presidential election.

But the road back looked like being a long one - and Mr Gore was still some distance from the starting line for 2004.

Campaign failure

Americans do not, as a rule, take kindly to a loser.

Hanging chads notwithstanding, Mr Gore is widely perceived to have made a mess of his 2000 campaign.

He never managed to take credit for the prosperity and peace enjoyed by the US during the Clinton years. Neither did he effectively distance himself from a president whose behaviour over the Monica Lewinsky affair had left a sour taste.

Gore: A committed family man

In many people's minds, his refusal to acknowledge defeat in the crucial battle for Florida went on too long and left him looking like a sore loser.

Mr Gore retreated for a time into a political shadowland. He accepted a temporary post as visiting professor at Columbia University in New York.

He also agreed to lecture on journalism, the family, and race relations at several other institutions - Fisk University and Middle Tennessee State, and the University of California at Los Angeles

Another project was to write a book on the changing American family with his wife, Tipper.

But commentators always believed he would find it hard to keep away from politics for long.

And he would not be the first candidate to have more than one shot at the presidency.

Richard Nixon took the oath of office in 1969 - eight years after narrowly losing to John F Kennedy.

Washington thoroughbred

Gore is very much a child of the Washington elite, his upbringing seemingly dominated by preparation for the White House.

He is the son of a senator whose ancestors fought in the Revolutionary War.

Educated at two of the nation's top schools and universities, his life has been geared towards duty. His mother even stopped his childhood violin lessons, saying: "Future world leaders do not play the violin."

His family kept a penthouse apartment at Washington's Fairfax Hotel where senior Democrats would often be seen debating policy with Senator Albert Gore Sr.

On leaving university, he enlisted for Vietnam despite his opposition to the war, fearing that his actions would otherwise bring electoral defeat on his father.

Call of office

Returning from serving as an army journalist, Gore entered newspapers before answering the call of high office.

At the age of just 28, he won his father's old House of Representatives seat in 1977 before moving up to the Senate eight years later.

In Congress, he earned a reputation as a technology specialist, focusing on issues such as arms control and funding for the then nascent internet.

In 1988, he made his ambitions clear when he audaciously launched a bid for the Democratic party's White House ticket at the tender age of 40.

The campaign flopped, but the senator earned respect with a best-selling book advocating public policy change to avert environmental disaster.

Clinton partnership

He ruled himself out of the 1992 race after his son was nearly killed in a car accident. Instead, he chose to sign up as vice presidential candidate with Bill Clinton.

Commentators describe the Clinton-Gore partnership as far closer than many previous presidential teams. The vice president took on a wide range of responsibilities, including the task of slimming down the federal bureaucracy.

And, while the president became embroiled in a deepening scandal over his affair with Monica Lewinsky, Al Gore led an apparently blameless personal life.

Married in 1970, he and his wife Tipper have four children. Mrs Gore is well known for her campaigns against the corrupting influence of rock music lyrics.