Here we go again. Today was the first day that the Court of Arbitration for Sport actually heard the Alberto Contador case. And, faithful readers of this blog will already know that Contador’s case will be heard over the next three days. Then, the waiting for a judgement begins. Will Contador be cleared of any wrong-doing? Will WADA and the UCI prevail and send the three-time Tour de France champion on a two-year “vacation” from competition? And will his results since then, including a win at the 2011 Giro d’Italia in May, be thrown out because of an unfortunate test result at the 2010 Tour?

On the surface, Contador’s case should be a simple one. Clenbuterol, the substance he’s accused of using, is banned in any amount. Even the paltry 50 picograms per milliliter concentration found in Contador’s test sample is enough to declare a positive test result. Given WADA’s strict liability rule, unless Contador can provide a compelling explanation of how the drug got there and why he’s not to blame, he’s in line for an automatic two-year suspension.

And that’s where clenbuterol cases get murky. Contador’s defense has been that he ate some contaminated beef, which must have caused the positive test result. This is similar to Jessica Hardy’s explanation that she used a contaminated supplement. Lucky for Hardy, she still had some the supplement on hand, and she was able to get it tested to show it was a possible source of her positive test result. But even though she could do all that, she still got a year’s suspension.

The problem for Contador can be summed up in the old question Clara Peller used to ask in the Wendy’s commercial back in the mid-1980s. “Where’s the beef?” Without a sample from the same animal, there is no way to establish whether Contador’s theory is correct. And yet, the Spanish authorities gave him a pass, which allowed the cyclist to continue competing during the last year. Which is how we got here, because WADA and the UCI appealed that decision to the CAS.

Who gets suspended and who doesn’t? Well, it depends in part on where you’re from. As Bonnie D. Ford points out in her piece on ESPN.com:

The fact that Contador wasn’t suspended floodlit one of the key weaknesses in anti-doping jurisprudence: There is no uniformity in who gets to judge the athletes in the first round of hearings. National sporting authorities have an inherent conflict of interest that legalistic bodies like the U.S. Anti-Doping Agency do not.

That isn’t the only weakness the Contador case highlights. Another weakness to the system is that some tests and some labs are capable of detecting amounts of banned substances that may be present due to environmental contamination. The question then becomes, what should be done when a very faint amount of a substance appears in an athlete’s sample?

There are several possible explanations in such a scenario. One, the athlete doped and the lab caught a faint trace of evidence as the drug clears his or her system. If no other tests were performed around the same time, it’s hard to rule out this explanation.

Another possibility is that the athlete was exposed to something contaminated (the Spanish steak brought across the border for Contador). Having other samples of the contaminated substance would help prove the point, as Jessica Hardy was able to do. But in Alberto Contador’s case, the test results didn’t become public until two months after the Tour was over. Why it took so long is unclear. But the chances are that by the time the results came out any remnants of the supposedly contaminated meat were long gone.

Yet another possibility is that the athlete received contaminated blood during a transfusion. For that, the authorities would need to show evidence of blood doping. Except, actually, they don’t. In an anti-doping case it’s up to the athlete to prove his innocence, and the authorities could hold evidence of blood doping in reserve as a way of contradicting Contador’s theory. (Although, that seems a bit silly to me. If they could get him for blood doping, I don’t see why they wouldn’t pursue such charges.)

Judging by what Bonnie Ford reports, the two sides have quite a list of people lined up to speak on their behalf.

A list of 23 witnesses combined for both sides in the Contador case was leaked to the Spanish press this week. It doesn’t include Hardy, and more’s the pity. The Contador panel might have been informed by hearing her testify about a year she lost and can never get back.

Instead, the panel will hear from hematology experts, nutritionists, anti-doping analysts, police investigators, a biostatistician, a polygraph expert (for the defense, although there is no confirmation that Contador has yet submitted to a lie-detector test), a small convoy of Contador’s 2010 Tour teammates, a representative from the Spanish beef industry and the butcher who sold the steaks to one of Contador’s friends. No word yet on whether either side plans to call a baker and a candlestick maker.

But here’s the rub. The only evidence that the CAS is likely to consider is that which relates directly to the case. Police investigators, biostatisticians and polygraph experts may be able to talk knowledgeably about various issues, but I wonder what they can actually contribute in terms of direct evidence for the test result in question. It reminds me of certain testimony in the Floyd Landis case. A witness may be able to speak to what cyclists believe to be effective doping techniques, but if he doesn’t have direct knowledge of what Landis did or didn’t do prior to his ill-fated come-from-behind romp through the Alps, the evidence will have no bearing on how the panel makes its judgement. Same for Contador. If the person testifying has no direct evidence about what happened the day he tested positive, most likely it won’t play a part in the panel’s final ruling.

Bonnie Ford (who I have great respect for) makes the argument that no threshold amount should be set for clenbuterol, as that would have the perverse effect of letting those who dope know just how much they can use without testing positive. That’s a fair point, I suppose. As this article points out, the success rate for catching dopers is pretty low to begin with. So giving the bad guys more ways to beat the system isn’t exactly a good idea.

The counterpoint that I would make is this: As tests become ever more sensitive to miniscule amounts of chemicals and drugs, reasonable thresholds need to be established so that someone who’s the victim of environmental contamination will not be penalized by a positive test result. There are levels of drugs that are so low that no possible doping benefit would occur. If an athlete’s sample comes back at such a low level, the reasonable thing would be to do some targeted testing, to see if it’s a one-time incident or if a pattern can be found that might indicate doping. If a pattern emerges, that would be the time to pursue a case.

Still, as Ford points out:

There’s little dispute that clenbuterol contamination in livestock is a reality in China and Mexico [ed. and Argentina and ...], and the U.S. Olympic Committee has openly warned its athletes to beware of what they eat there.

But until and unless those countries are persuaded to clamp down on their agricultural establishment (and shouldn’t they do that for the sake of their general citizenry as well as elite athletes, since clenbuterol can cause some nasty side effects and is nothing to mess with?), doping cases that originate there involving resident or visiting athletes will continue to be headaches for anti-doping authorities.

Indeed, these cases will be headaches for the ADAs. But a little common sense on what amount triggers a positive test result could go a long way to reducing the number of headaches.

Regardless of what should be, the rule in place today is strict liability. No amount of clenbuterol is allowed. And unless Alberto Contador can come up with the beef, fair play requires that he be suspended for two years.