In the 1996 U.S. Senate race in Massachusetts, the wise guys in the Boston media and political establishment toasted Gov. William Weld and made fun of incumbent Sen. John Kerry. Kerry was mocked as a phony and a publicity hound--dubbed "Live Shot" by Billy Bulger, the Massachusetts state Senate president. Weld, on the other hand, was seen as clever and cool, the witty star of Bulger's annual St. Patrick's Day breakfast. If you had to guess which of the two candidates would do better on "Imus in the Morning," the irreverent talk show that has a large New England audience, you wouldn't have guessed John Kerry.

You would have guessed wrong. Appearing on "Imus," Weld, who can be a little lazy, was unprepared and flat. "He didn't recognize my enormous influence," recalls Don Imus. Kerry came ready with jokes and riffs, but more important, he was not rattled by the razzing of the mercurial Imus. ("You can ask him questions like 'Is your wife too nutty to be First Lady?' " says Imus.) The talk-show host endorsed Kerry, stamping him as a regular guy and helping him win re-election that November.

Kerry's performance in the Imus primary of 1996 is a small but telling example of why it is a mistake to underestimate the junior senator from Massachusetts. Because Kerry can seem stiff, lordly and pompous, it's easy to assume that he is also a balloon that will pop, a facade that will crack. The opposite is true. "I'm known as a good closer," Kerry says with characteristic immodesty, a man who is tough in a close fight. His past suggests that he is telling the truth.

In an interview with NEWSWEEK, Kerry attributed his drive to his parents, who "set very high standards." Kerry's father, Richard, was a career State Department employee, an austere, somewhat disillusioned figure who never, to his regret, made ambassador. The Kerry dinner table was a nightly foreign-policy seminar. While other boys were eating TV dinners in front of the tube, Kerry was discussing George Kennan's doctrine of containment. An avid sailor, Richard Kerry taught his son to navigate the hard way: by blindfolding him in the fog and making him figure out how to get home. Kerry's childhood seems rather lonely. As a little boy, he was moved from place to place before attending a "very strict" school in Switzerland, where he was one of only three English-speaking boys. Kerry learned, at an early age, to depend on himself.

At St. Paul's, a posh prep school in New Hampshire, Kerry was not popular. On the hockey team, he was called "Keep-the-Puck Kerry" because he didn't like to pass to his teammates as he skated toward the goal. Barging into pickup games on the school's frozen ponds, he was known for stealing the puck from younger boys and shooting it into the woods. At a Republican Episcopalian school he was a Democrat and a Roman Catholic who worshiped John F. Kennedy. The boys reportedly joked that his own initials--also JFK--stood for "Just For Kerry." (Kerry told NEWSWEEK that the nickname is "bogus," made up a few years ago by a mean-spirited Boston Globe columnist.) Prep-school boys of that era were not supposed to grasp or grind; the ideal was "effortless grace." Kerry committed the cardinal schoolboy sin of showing his ambition.

The sneers "did bother John a lot," says Danny Barbiero, a classmate who was also a social outcast. "He's a lot more sensitive than he shows." Kerry's answer, says Barbiero, was: "Be better." He excelled at everything. At Yale he played wing on the soccer team (scoring three clutch goals in his last game against Harvard), was elected president of the Yale Political Union and was tapped by Skull and Bones. The last was sweet revenge: most of the preppies who made fun of Kerry would have given their trust funds to be tapped by the elite secret society.

As a young naval lieutenant and Swift Boat captain, Kerry struck some of his fellow officers as a condescending glory-seeker. By trying to imitate JFK's PT-109 exploits, he was supposedly putting his men at risk. But his enlisted men did not see it that way, according to historian Douglas Brinkley, who interviewed Kerry's crews for his new book, "Tour of Duty: John Kerry and the Vietnam War." The enlisted men "were suspicious at first," says Brinkley, because Kerry had longish hair for the military (the Kennedy look again). But they quickly learned that they could depend on him as a brave--but not foolhardy--combat leader. Kerry the amateur yachtsman was a very skillful boat handler; fluent in French, he was able to read old colonial river maps.

Kerry's sincerity was questioned again when, as a prominent member of Vietnam Veterans Against the War, he joined other vets in throwing their medals on the steps of the Capitol. Kerry threw only his combat ribbons; the actual medals he kept. The first time he ran for Congress, from a blue-collar Massachusetts district in 1972, he was regarded as a carpetbagger, and lost in an upset. Kerry was almost catatonic after the defeat. But according to his campaign co-manager and Yale roommate David Thorne, he learned a valuable lesson: "Never take anything for granted." When Kerry ran for the U.S. Senate in 1984, his opponent for the Democratic nomination, a very popular congressman named Jim Shannon, remarked--a little too casually--that Kerry was trying to have it both ways as a war hero and antiwar activist. Kerry hit back hard, rallying veterans to beat Shannon.

Shannon today downplays the veterans' vote but credits Kerry's "intense focus." Kerry has a "great survival instinct," he says. "He is willing to change his style if he has to. Most politicians aren't willing to change. He'll do what he needs to do."

In Iowa, that meant shortening his windy stump speech from 30-45 minutes to 15-20 minutes and sounding less like a stuffy Brahmin professor. Kerry began striking some populist themes, railing against "Benedict Arnold" corporations. He listened more. He sounded less entitled and more humble. He stopped attacking his opponents (and dumped campaign staffers who pushed him to go negative). He drove himself to exhaustion, allowing voters to see a hint of vulnerability beneath the perfection. But only a hint, and only for a moment.