Entertainer Jay Leno isn’t a sports reporter or analyst, but his recent on-camera conversation with bicyclist Floyd Landis was a penetrating and disturbing interview worthy of a professional journalist.

Landis is the American who seemingly overcame tremendous odds, primarily a severely deteriorated hip, to win the famed, but increasingly infamous, Tour de France. Then urine tests indicated he had illegal performance-boosting substances in his body. While the system is supposed to presume innocence, there is growing evidence that an abnormal level of performance-enhancing testosterone factored into Landis’ victory. As of now, it seems he will lose his title and suffer the accompanying disgrace.

Landis and his attorneys insist nothing was amiss, and he has been making the rounds of talk shows to try to plead his case. But Leno on his “Tonight Show” was not interested in a whitewash.

“I see you on these shows,” Leno said, “and I do want to believe you and the evidence seems – I don’t know if it’s overwhelming – but it seems pretty conclusive, right?”

Landis said yes, if one goes by the tests, and Leno quickly, and appropriately, responded: “Why should we not go by the tests? Tell me why.”

Landis didn’t have a good answer. It is a sad situation because if he has been involved in doping he has betrayed many who rooted for him and honored him when he apparently won the grueling race.

One of the most unfortunate aspects of this and other cases of “doping” is public cynicism and skepticism they breed toward sports competitions. Any more, fans are inclined to suspect that any brilliant or exceptional athletic feat is a result of the kind of cheating Landis is accused of.

As Leno pointed out, people really want their stars and superstars to be “clean and honest” and are so pleased and proud when they are. But there are enough sad cases in sports now that people presume guilt until innocence is firmly established. Even then, no matter how many or intensive the tests, there are doubters.

It is a sickening trend in many sports, and it is a shame officials and their laxity in demanding preventive procedures have allowed things to deteriorate to this sorry state.