A great strength of American society is the drive to succeed — well, not just to succeed but to do better than anyone else; to be a star, a tycoon, an authority, a power, a celebrity, or a leader; to be admired, respected, feared, or obeyed more than your peers.

It is the belief in these possibilities that motivates countless Americans to strive for excellence, to work hard and to search for new discoveries and inventions. As for one of the great weaknesses of American society, see all of the above.

It is an enduring paradox of the American condition. There is a point at which ambition and the determination to succeed, which generally serve us well, turn destructive, corrupting, and dishonest. Success becomes its own god. Winning is what matters; the methods or consequences count little or not at all.

The latest reminder of the paradox comes from three recent cases: Bill Belichick, the coach of the New England Patriots; runner Marion Jones; and trial lawyer William Lerach. Mr. Belichick had opponents’ defensive signals videotaped, contrary to explicit National Football League rules; Ms. Jones admitted taking illegal drugs around the 2000 Olympics; and Mr. Lerach pleaded guilty to illegally hiring plaintiffs as fronts for filing suits against companies. Mr. Belichick got off fairly easy, a $500,000 fine, but the others did not. Ms. Jones has returned five medals — three gold, two bronze — won at the Sydney Olympics, and Mr. Lerach faces $8 million of penalties and at least a year in jail.

What connects these cases is that the transgressions were largely, or perhaps entirely, pointless. Does anyone really believe that Belichick’s Patriots didn’t win three Super Bowls (2002, 2004, 2005) on inherent ability? Ms. Jones almost certainly would have earned some medals without doping. Mr. Lerach was among the kingpins of trial attorneys. Although he might have missed some suits by not having dummy plaintiffs, his firm surely could have remained in the top tier while abiding by the rules.

On the whole, Americans believe in ambition. They think it’s necessary for them personally and valuable for society. In one survey, the National Opinion Research Center at the University of Chicago asked respondents what mattered for “getting ahead in life.” Ambition ranked first at 43%, followed closely by “hard work” (38%) and “a good education” (36%). Lagging behind were “natural ability” (13%), “knowing the right people” (10%), “educated parents” (6%), “coming from a wealthy family” (3%), “having political connections” (3%) and “a person’s race” (2%). Americans think that individual effort counts; other stuff is secondary.

It is not just that we endorse ambition. We’re also fascinated by it. “American Idol” and its many imitators — “Top Chef,” “Project Runway,” “The Last Comic Standing,” among others — are not about singing, cooking, designing clothes, or telling jokes. As political scientist Benjamin Barber notes in the current Wilson Quarterly, these shows are “about winning and losing.” That’s why they’re so popular; they’re a televised metaphor of what many Americans live every day.

Superficially, we want to know the outcomes. But the real draw of these programs is that we live vicariously through the contestants’ dreams and disappointments. Almost all of us want to be a champion; almost none of us can be.

We sympathize or identify with upstanding losers, who, despite strenuous efforts and personal integrity, fall short. We cheer winners whose talent and hard work merit success. We’d like to be in their spot. But we dislike a conniving victor who, even if talented, seems a creep or fraud.

By and large, most Americans reconcile ambition’s high demands with real-world limits. The essayist Daniel Akst, also writing in the Wilson Quarterly, sensibly warns:

“Life is not as competitive as the media might have us believe. Most Americans have more leisure than they did a generation ago, even as the highest-paid earners work like maniacs. And competition of all kinds is worst in places such as New York and Los Angeles, where real-estate hysteria and preschool panic afflict even the rich and powerful. The media come to us from these places … (and their reports) should be discounted by at least 50 percent.”

Fair enough. But for a subset of Americans, ambition becomes unmoored from anchors of good judgment, widely accepted social norms, or ethical values. It becomes fanatical, a force that sometimes produces astonishing accomplishments and sometimes tragedy, misery, and glaring lapses in behavior — and occasionally all of them together. The stories of Belichick, Jones, and Lerach attest to that.

As ambition inflates, so does self-absorption. Everything else in life deflates. The single-mindedness can smother selfrestraint and common sense. It’s a big downside.