Various polls showed Senator John Kerry was lagging behind President George W. Bush before the first face-to-face presidential debate Thursday, which will be pivotal for the White House race.

But the Massachusetts senator, 60, is well known for seizing the last moment to win a come-from-behind victory. He won at least three such victories.

After graduating in 1966 from Yale University with a bachelor of arts degree, Kerry joined the US Navy and served in Vietnam from 1968-1969. He became a hero after winning a Silver Star, Bronze Star and three Purple hearts as a swift boat officer.

Returning from Vietnam, the war hero turned to an anti-war hero.Kerry made a name for his famous line when testifying before a Senate committee: "How do you ask a man to be the last man to die for a mistake?"

Kerry's first foray into politics was not successful. In 1972, 28-year-old Kerry declared his candidacy in the 5th Congressional District in Massachusetts but lost the bid.

After the defeat, Kerry went to Boston College and got a law degree in 1976. He worked as an assistant district attorney and opened his own law practice. But he never gave up his political ambition.

In 1982, Kerry was elected Lieutenant Governor of Massachusetts. In 1984, he was elected to the US Senate, where he is currently serving his fourth consecutive term.

In these two elections, Kerry upset a favored Democratic rival for the party's nomination.

In the days leading up to the first caucuses in this year's primary season, Kerry was considered by many to be dead in the water. But Kerry won a landslide and never looked back.

Before Kerry's first face-to-face encounter with Bush, polls show voters giving him an edge on a number of domestic issues like social security, health care and the economy. But he will have to use the debates to convince Americans he is a strong leader and firm commander-in-chief.

The Republicans and the Bush campaign have portrayed Kerry as a flip-flopper who keeps shifting positions on key national security issues such as Iraqi war and terrorism. This campaign proved to have effectively damaged Kerry's image and eroded his support.

Kerry is married to Teresa Heinz Kerry and has two daughters by a previous marriage. Teresa Heinz is the widow of late Republican Senator John Heinz of Pennsylvania and has an estimated fortune of 600 million US dollars.