In the past year, McCain led a Senate effort to expose U.S. Olympic drug cheats before the 2004 Summer Games, took on boxers' safety issues, and now helps guide a proposed multi-sport steroids crackdown that hauled a handful of big league baseball stars before a congressional committee in March.
Critics question whether McCain and his congressional colleagues are meddling or grandstanding.
McCain replies that professional sports have become about far more than the games. He says sports and society are so intertwined that athletic scandals invariably have political or social consequences. "The fact is that professional athletes are such incredible role models," McCain says.
His efforts have produced incremental results. McCain has learned well that the lords of professional sports don't always appreciate what some consider unwarranted federal intrusions. The senator has at times grown frustrated with baseball and its players union for moving slowly to address the problem of steroids.
Donald Fehr, the baseball players union chief, says the bill being pushed by McCain and others - calling for a minimum two-year suspension for baseball, football, basketball and hockey players for a first steroid violation - represents an overreaching, "one-size-fits-all approach."
McCain has heard similar complaints from boxing insiders. Fight promoter Bob Arum questions whether the government should establish a federal boxing authority that McCain proposes to prevent unqualified boxers from being abused in the ring. Says Arum: "It could be very good. It could be very terrible. A lot of whether it's good or bad will depend on who the personnel are."
But McCain has had some noteworthy success. Fearful that steroid-using U.S. Olympians were headed to last year's Athens Games, he took the bold step of pushing a Senate committee to subpoena documents from a federal criminal investigation of an alleged steroid distribution conspiracy. After receiving the evidence, the committee turned it over to the U.S. Anti-Doping Agency. Olympic observers say they believe the United States sent a cleaner team as a result.
"The handing out of penalties to certain track athletes is almost exclusively due to the proactive intervention of Senator McCain and his committee working with the USADA," says New Jersey-based sports agent and lawyer Jerrold Colton.
McCain says his unofficial sports role came naturally. "I would imagine if I wasn't a sports fan, I wouldn't have this kind of involvement," he says.
A boxer when at the Naval Academy, McCain, 68, is such a sports junkie that during basketball season, "he'll go home, go to bed after the last vote but set his alarm to get up and watch the [Phoenix] Suns," says Mark Salter, his chief of staff.
When grilled by captors in a Hanoi prison camp during the Vietnam War, the former Navy aviator rattled off the members of the Green Bay Packers' defensive line instead of the names of a U.S. squadron the inquisitors were pressing for, Salter said.
McCain, who grew up idolizing baseball star Ted Williams and boxer Sugar Ray Robinson, is especially passionate about fixing boxing, a sport he says suffers because state commissions allow ill-qualified fighters to compete and because a confusing "alphabet soup" of organizations each claims a champ.
McCain, a scrapper in the Senate, was equally spirited in the ring, says Robert Timberg, a former Sun journalist whose 1995 book The Nightingale's Song chronicled the lives of McCain and other Naval Academy graduates. "Unschooled as a boxer, McCain would charge to the center of the ring and throw punches until someone went down," Timberg wrote of McCain's immediate post-induction period in 1954.
At its best, McCain says, boxing is capable of grandeur. "There's something about some matchups that's transcendent," he says. "Some of the greatest sporting events of the 20th century were the Muhammad Ali fights."
But along with the sport's soaring highs come depressing lows, the senator says. Mexican fighter Ruben Contreras suffered a severe head injury in a recent Los Angeles fight with American Brian Viloria and was hospitalized. The result raised questions among boxing insiders about whether Contreras belonged in the ring and about how many fighters lack the proper health or credentials.
The senator's bill would create a three-member, president-appointed body to oversee boxers and promoters and establish standards for issuing fighters licenses. Approved by the Senate, it is awaiting action in the House.
It remains to be seen how McCain's sports efforts will affect him politically. The 2000 presidential candidate might run again, in 2008.
Rasmussen Reports, a public opinion research firm, reported recently that baseball fans widely believed that steroids had tainted recent home run records. But the firm also said fans generally want Congress to stay out of the controversy.
A handful of House members who once said they didn't see the need for congressional intervention now support the bill. Some of their conversions came after a March hearing on steroids in baseball attracted more media interest than any congressional event since President Clinton's 1998 House impeachment.
It's a far cry from the 1990s, "when McCain and [North Dakota Democrat] Byron Dorgan would hold hearings on boxing and they were virtually the only senators who showed up," said former McCain aide Mark Buse, a governmental affairs consultant.
While McCain is gratified there is more interest, he said he sometimes feels as powerless as any other fan.
One of his pet peeves is the high cost of pay-per-view boxing matches - a fee the senator says is driving fans away.
"I always vow that I'm not going to pay the $49.95, and then 15 minutes before the fight, I do," McCain says. "I say, 'Ohhhhhh!'" he says in a groan that mocks a fan's surrender to the sport.
Sun staff writer Lem Satterfield contributed to this article.