VAUGHTERS HAD a good but not great pro cycling career for ten years, racing with Lance Armstrong's U.S. Postal Service team in 1998 and 1999 and competing in, but never finishing, four Tours de France (two crashes, one wasp sting, and one case of exhaustion). He retired from racing in 2003, at just 30. "I'd had enough of it," he said. "The doping, being away from my family. And I was tired of disappointing people. I was supposed to be in the top ten percent of riders, but with my physiology I couldn't recover well without doping."

Vaughters, whose slight build, angular glasses, and tapered sideburns make him look more like a lit professor than a former professional athlete, all but confesses to having used performance-enhancing drugs. But he refuses to be, well, 100 percent transparent.

"I can't do anything about what I did in the past, and I can't make a confession. That would draw so much attention away from the team," he said. "Anyone who knows me knows I'll be perfectly honest about it in private, one on one, but I don't want to talk publicly about things I did years ago."

So he's running a no-secrets anti-doping program, I pointed out, but he won't say whether he did or didn't? "With all I've told you," he responded, "if someone can't read between the lines ..."

A year after retiring, Vaughters dallied with real estate, then started a junior team, which became TIAA-CREF, the leading U.S. developmental squad. He wasn't an anti-doping crusader yet, but he didn't like the prospect of his riders encountering the pressures he'd seen in the pro ranks. "I'm very driven by protecting the young riders," he told me. "They've never been faced with the decision of whether to dope or not. And they shouldn't have to be."

His first hint at a solution came when he read a July 2005 article in Outside about Don Catlin, the former head of the UCLA Olympic Analytical Laboratory and one of the world's top experts on testing. Catlin, now CEO of the nonprofit group Anti-Doping Research, suggested replacing the old model of looking for specific drugs with one that searched for their effects on certain biomarkers in the body, including red blood cells, growth hormones, and natural steroids. Every person has different naturally occurring levels of these, and Catlin's idea was to create a profile, or "biological passport," of each athlete's biomarkers, and then monitor them over time. Any suspicious changes—say, a sudden spike in the ratio of red cells or a steady ratio during a long race (when it should dip)—would be clear evidence that something shady was going on.

Vaughters liked the idea. He had been talking to Doug Ellis, a wealthy investor and cycling fan from New York who wanted to back a professional American team. Ellis agreed to fill in any financing gaps not covered by corporate sponsorships, and Slipstream was born. (Slipstream is Ellis's sports-management company, named for a cycling-themed screenplay he wrote.) In September 2006, they signed a contract to start working with the Agency for Cycling Ethics, a new, private Los Angeles company—one of its founders, Paul Scott, had worked for Catlin—that offers biomarker profiling.

In January 2007, ACE testers started making visits to the Slipstream training camp, drawing blood and taking urine. (In the red stuff they watch for the effects of EPO, transfusions, and growth hormones; in the yellow, steroids.) Most pros are tested about ten times a year, at races or by outside authorities like cycling's governing body, the Union Cycliste Internationale (UCI), and the U.S. Anti-Doping Agency (USADA), which has authority to test riders on American teams or at American races. By the end of Slipstream's first year, each of its riders had undergone as many as 40 additional tests—some scheduled, others random—at a cost of $350,000, about 10 percent of the team's total budget. The program's price tag will reach $500,000 this year.

Slipstream had modest success in 2007, including a team win at the inaugural Tour of Missouri. But while some of cycling's biggest names were being nailed for doping, not a single Slipstream rider failed a test.

The sport noticed. CSC and Astana instituted biological-passport systems through a program headquartered in Denmark, and T-Mobile (now Team High Road) signed with ACE. All three are in the ProTour, cycling's version of the major leagues. Eleven ProTour veterans—including Millar and American David Zabriskie, another former yellow-jersey wearer—signed with Vaughters for 2008, even though Pro Continental teams like Slipstream have a much tougher time getting invites to major races. Then, in October, the paradigm shift started to go global. The UCI announced that it was instituting a mandatory biological-profiling program across the ProTour in 2008, while still performing the usual in- and out-of-competition tests.

"The biggest thing we did was show that there were teams that would accept doing voluntary testing," Vaughters said as we followed Slipstream's riders up a long hill one afternoon. "A critical mass of teams said they'd do this in 2007. Before, the UCI believed no one would accept it." The first race conducted under the UCI's new policy was the Tour of California.

I asked Vaughters if he thought there were still guys in the peloton who were taking performance-enhancing drugs. "I don't know," he said. "If you had asked me several years ago, the answer would have been yes." He paused. "I think the possibility exists today that no one is."