U.S. hammer thrower John McEwen, who tested positive for the designer steroid THG last summer, refused to testify at his arbitration hearing in April. U.S. Anti-Doping Agency lawyers prosecuting the case argued that his silence should be held against him.

USADA said McEwen's unwillingness to testify was the equivalent of an admission of intentional doping and should be grounds for increasing his suspension from two to four years, sources said. In their decision, the arbitrators did not specifically address the matter, but they declined to enact a four-year ban.

The case was brought to the attention of the U.S. Olympic Committee's Athletes Advisory Council, which is considering petitioning for rule changes that offer athletes greater protection in future arbitrations, according to sources, and could resonate significantly in the Bay Area Laboratory Co-Operative (BALCO) drug scandal, which is on the cusp of arbitration hearings for four U.S. track athletes notified last week of potential drug violations by USADA.

USADA is expected to decide this week whether to press forward with formal charges against Tim Montgomery, Chryste Gaines, Alvin Harrison and Michelle Collins. If USADA does bring charges, the matters would move to arbitration under the Court of Arbitration for Sport.

The athletes' testimony in front of three-judge arbitration panels and how it might be interpreted -- namely, how much weight might be attached to an athlete's refusal to testify -- are likely to be crucial issues at the hearings given that cases are built on circumstantial evidence seized in a federal raid of BALCO last fall.

None of the athletes failed a standard drug test. USADA has been unable to secure the cooperation of indicted BALCO owner Victor Conte, perhaps the only person who could say for certain whether the athletes received or took banned or improper drugs.

Except, of course, the athletes themselves.

The Fifth Amendment right against self-incrimination applies only to matters in criminal court; there is no such protection in civil matters. Olympic drug cases, however, have traditionally fallen somewhere in between. In international sport lingo, they are considered "quasi criminal" disciplinary hearings.

In some cases, Court of Arbitration for Sport (CAS) panels have applied specific principles of criminal law to doping matters, according to a 2003 legal opinion on the World Anti-Doping Code by Gabrielle Kaufmann-Kohler.

"Because this is a quasi criminal proceeding, the 'taking the fifth' issue is going to be weighed pretty heavily" by the arbitrators, said an attorney who has been involved in a number of CAS arbitrations but who doesn't represent any BALCO athletes.

Some track athletes might argue that it doesn't matter whether USADA is a criminal court; as long as the BALCO case is ongoing, anything they say in front of any tribunal could eventually be used against them in U.S. court.

There are, perhaps, other incentives for silence. Two sources close to the BALCO case said that some athletes, granted immunity from prosecution, admitted wrongdoing when they testified under oath before the BALCO grand jury. Those athletes could find themselves cornered. Though no athletes followed through on USADA's request to obtain transcripts of their testimony, all are essentially bound by what they told the grand jury.

"If I had an athlete, I would make clear that we cannot get on the stand and contradict what we said to the grand jury," said Jerrold Colton, the attorney for Kelli White, who accepted a two-year ban from USADA after the agency presented her with evidence of wrongdoing.

Though such a contradiction might serve the needs of the moment, the athlete could eventually face perjury or obstruction of justice charges from federal prosecutors if his or her grand jury testimony were later unsealed. In short, the best course for athletes in such a position would be to refuse to testify and hope the arbitrators did not penalize them for their silence.

Pleading the fifth has rarely, if ever, been taken in USADA hearings prior to the McEwen case, so there is little precedent on the matter.

Should athletes decline to answer specific questions, USADA is expected once again to urge the arbitration panel to draw negative inferences, which could significantly bolster cases that athletes' attorneys claim are otherwise filled with holes. In fact, unlike in the McEwen case, in which the negative inference would have meant merely the difference between a two- and four-year ban, a negative inference in the BALCO case could be the difference between guilty and not guilty.

"There are tremendous consequences to the athlete," Colton said.

Despite the Athletes Advisory Council's interest in the issue, no rule changes could be enacted in time to affect the BALCO cases. AAC Chair Rachel Godino declined to discuss the specifics of pending business matters. USADA Director of Legal Affairs Travis T. Tygart has repeatedly declined to comment on issues related to specific cases.

USADA officials, however, have made their stance clear: They believe that since they lack the subpoena power and other investigative advantages inherent in true criminal prosecutions, they should not be held to the highest standards of proof or restraint -- i.e., criminal standards -- in their proceedings against athletes.

Attorneys argue that if negative inferences are allowed to be drawn in USADA arbitrations, athletes in cases in which grand jury testimony doesn't loom in the background might find incentive to lie.

Howard Jacobs, who represented McEwen and is now part of Montgomery's legal team, said the precedent also could make for a less rigorous process of bringing charges in the future.

"That could open the door to USADA bringing charges against athletes when they know they don't have sufficient evidence, in the hopes that they can convince arbitrators that the negative inference alone is enough of a basis to suspend an athlete," Jacobs said. "It's a new McCarthyism, it seems to me. Either you have the evidence or you don't."