Senator Joseph Lieberman of Connecticut, selected by Mr Al Gore as his vice presidential running mate, has the reputation of being politically independent, tough on military issues and morally impeccable.
As the only orthodox Jew in the Senate, Mr Lieberman (58) observes the rigid dietary laws of Judaism. On the Sabbath, he will not travel, write, engage in political activities or use electricity. And he says he is deeply influenced in his political life by Jewish ethics and texts.
"It's a wonderful organising principle of my life. It gives it order, a sense of purpose, but it also provides me, in terms of the Sabbath, with a sense of sanctuary in my week which has become more important to me as I've gone on in life and become busier," Mr Lieberman said in 1997.
"There's no question that my religious upbringing and my religious education was a major contributor to who I am. And who I am determines how I vote on particular issues," he said.
One example is his commitment to a strong national defence policy, which has sometimes put him at odds with his fellow Democrats. He said that goes all the way back to when he was 13 and had his bar mitzvah.
At the ceremony, he read a passage from Exodus telling how the Amalekites attacked the Children of Israel from the rear, an act that the Bible says could neither be forgiven nor forgotten.
Mr Lieberman backed the 1989 US invasion of Panama and was one of the leaders in the fight for a resolution backing the 1991 Gulf War.
On another issue, abortion, Mr Lieberman finds himself at odds with most conservative Christians.
"When I was in the state senate I would agonise and agonise over this. And I did occasionally consult rabbinical sources over the generations. Ultimately I decided that, after all my struggling with this question, we really had to respect the right of women to choose," he said.
Mr Lieberman's defining moment came on September 3rd, 1998 when he became the first Democratic senator to denounce Mr Clinton for his behaviour in conducting an affair with the White House intern, Ms Monica Lewinsky.
In a speech spiced with quotations from past presidents and delivered with quiet authority, Mr Lieberman said Mr Clinton's behaviour was not just inappropriate.
"It is immoral. And it is harmful, for it sends a message of what is acceptable behaviour to the larger American family, particularly to our children," he said.
Mr Lieberman grew up in Stamford, Connecticut, the son of a liquor store owner. He went to Yale University where he first became involved in politics and helped found an anti-Vietnam War group. In 1970, he ran for the state Senate against the sitting majority leader and won. One of the volunteers in that campaign was a young Bill Clinton. Senator Lieberman was seen as certain for re-election to the Senate this November.