GENEVA (AP) Much of the intense Olympic action before the Rio de Janeiro Games open in less than two weeks is set to play out in the law courts.
For many Russian athletes caught up in a doping scandal, a legal fight - and a race against time to get the verdict they want - is their biggest barrier to competing.
The Court of Arbitration for Sport already handed one defeat to Russia on Thursday. It rejected an appeal by 67 Russian track and field athletes who the International Association of Athletics Federation had declared ineligible for Rio after previously banning their national federation from international competitions.
On Sunday, the International Olympic Committee's executive board will consider banning all Russian teams from the Summer Games because of a state-sponsored doping conspiracy.
If the IOC imposes the toughest punishment, the Russian OIympic committee could then also challenge it at CAS, which opens a special Olympic court in Rio next week.
Cases can go above world sport's appeal court. Just a short walk from CAS's headquarters in Lausanne is Switzerland's supreme court - the Swiss Federal Tribunal.
Russian sports minister Vitaly Mutko already suggested that the 67 athletes could ''defend their honor and dignity'' by going to a higher civil court.
Many try but few succeed in persuading Swiss federal judges to overturn CAS verdicts.
WHO CAN APPEAL A CAS VERDICT?
Anyone who loses before a typical three-member panel of CAS judges can file a further appeal at its home country's highest civil court, the Swiss Federal Tribunal.
A federal case is slow and tough to win, with few grounds of appeal.
Federal judges intervene if legal process was abused but will not re-examine the merits of a case.
A faster option for Russian appeals would be for a provisional measure - an interim ruling to freeze a verdict pending the full case.
WHO HAS BEATEN CAS AT FEDERAL COURT?
Very few cases, at a rate of about one per year of around 400 arbitration and appeal processes annually.
It is even possible to overturn a CAS verdict in the federal court and still lose the re-trial. That happened to tennis player Guillermo Canas of Argentina in 2007.
Canas was initially banned for two years by the ATP Tour's anti-doping tribunal, and saw that reduced to 15 months at CAS.
When Canas went to federal court, Swiss judges ruled his right to be heard had been breached and sent back the case. A second CAS hearing also applied a 15-month ban.
WHAT'S THE BEST WAY TO BEAT CAS?
Federal judges have set aside several verdicts on the grounds that CAS did not have jurisdiction to judge the original case. Those cases include a win and a loss for the International Ice Hockey Federation.
The IIHF lost to a German international player whose ban for refusing a doping test was overturned. It then won a million-dollar compensation case against Swiss hockey champion Bern.
CAS had awarded the club damages for lost earnings when the 2009-10 Champions Hockey League folded due to the main sponsor, Russian energy giant Gazprom, pulling out.
IS THERE AN EXCEPTION TO GIVE RUSSIA HOPE?
The case of Brazilian soccer player Matuzalem stands out for federal judges intervening to say: ''Enough is enough.''
He won a supreme court ruling in 2012 over a ''manifest and serious attack on his rights'' by FIFA and CAS.
Matuzalem broke his contract to force a transfer and was ordered to compensate his former club, Shakhtar Donetsk of Ukraine, around $15 million.
When the player struggled to pay, and broke FIFA's disciplinary rules, he filed a further round of appeals to CAS and the federal court.
Federal judges objected to Shakhtar having the power to request a ban, which itself could curb Matuzalem's ability to earn and repay the debt.
''In exceptional cases, a sentence can be annulled for violation of the essential principles of the judicial system, named `the public order','' the federal court said.
Could Russian authorities or athletes eventually persuade Swiss judges that an Olympic ban is a similar violation?
Unlikely, but perhaps not impossible.