Floyd Landis says not in this case.
The evidence so far says he'd better have a good lawyer.
Make that a great one.
On Thursday, Landis denied ever injecting testosterone or using a steroid patch - a single dose applied for six hours that's enough to speed recovery, but not enough, usually, to be detected. He was considerably less clear, though, about what else could have triggered a positive test.
Landis said there's a chance his body naturally produces way more testosterone than just about everybody else on the planet. That's plausible, but improbably rare.
Either way, a more sophisticated screening test called an IRMS will clear that up soon enough. Landis didn't sound like he was holding his breath.
Then there were the cortisone shots he took to make riding on a crumbling right hip just bearable. But experts in the field of performance-enhancing drugs ruled that out as a cause. Besides, Landis was already in the clear on that count; he had a medical exemption for taking cortisone.
Half-seriously, he mentioned beer. The same experts pointed out that Landis better be joking.
Next, Landis revealed that he's been combatting a "thyroid condition" for the last year, and wondered whether that medication goosed his testosterone-epitosterone ratio to levels that prompted Tour de France organizers to think about asking for their yellow jersey back.
At least Landis didn't say the dog ate his homework. And he had had the good sense to recognize how lame those explanations sounded moments after he piled them up.
"I wouldn't hold it against somebody," Landis told the magazine, "if they don't believe me."
Landis began a news conference a few hours later sounding gloomier still. He is certainly savvy enough to know no athlete gets the benefit of the doubt anymore, at least not when "performance-enhancing" and his name wind up in the same sentence.
"Unfortunately, I don't think it's ever going to go away no matter what happens next," he said. "It appears as though this is a bigger story than winning the Tour, so that's going to be hard to go away."
And what makes this one bigger still is not just why it could have happened, but when.
The sample that came back positive was taken from Landis last Thursday, soon after he tied off one of the most remarkable comebacks in the storied history of the race. Just 24 hours earlier, Landis fell apart on the 113-mile trek up the Alps to La Toussuire and his chances of winning left for dead. Landis got up the next morning a different man, and almost single-handedly, willed them back to life.
He attacked on the first climb back up the same mountain range, a 125-mile stage to Morzine-Avoriaz, and didn't stop until he'd broken every rider in his path. Now it appears he broke something just as elemental: trust.
For almost a week, that ride was one of those performances that people in and outside the sport couldn't stop talking about, something that made them believe there was no limit on how far hard work, toughness and a willingness to sacrifice could carry a champion. Now it's just one more reason to be skeptical about the next great performance, the latest "Exhibit A" for the argument that anybody that good in a dirty racket has to be dirty, too.
Another good-guy American cyclist named Tyler Hamilton said some of the same things in the court of public opinion when he got caught. Hamilton kept insisting all he needed to prove his innocence was time. That was two years ago.
The cases were different - Hamilton, whose crowning achievement was an Olympic gold medal, tested positive for blood-doping - but Landis' already looks uncomfortably familiar. And the clock just started ticking.
Jim Litke is a sports columnist for The Associated Press. Write to him at email@example.com