Olympic champion LaShawn Merritt was cleared to defend his 400-meter title in London next year after the American won his appeal Thursday against an IOC rule banning doping offenders from the games.
The Court of Arbitration for Sport annulled the International Olympic Committee rule that bars any athlete who has received a doping suspension of more than six months from competing in the next Summer or Winter Games.
The three-man panel said the rule, adopted in 2008, was ''invalid and unenforceable'' because it amounted to a second sanction and did not comply with the World Anti-Doping Agency code. It said the rule amounted to a ''disciplinary sanction'' rather than a matter of eligibility.
Merritt, the American 400-meter gold medalist in Beijing, had been ineligible under the IOC rule to compete in London even though he completed his doping ban earlier this year after testing positive for a banned substance found in a male-enhancement product.
The US Olympic Committee challenged the rule and was backed by several other national Olympic and anti-doping bodies. The IOC maintained it had the right to decide who is eligible to take part in its games.
The IOC said Thursday it ''fully respects'' the verdict and will comply with it. However, the IOC said it would push for the rule to be included in a revised WADA code in 2013.
The CAS decision means Merritt becomes eligible to compete in London, as do other athletes around the world who have been affected by the rule.
''We're obviously happy about that,'' USOC CEO Scott Blackmun said. ''LaShawn made an error that he even admitted was a silly error. We're glad he's going to be able to compete.''
Other athletes affected by the ruling, according to CAS, include Brazilian cyclist Flavia Oliveira, Hungarian wrestler Balazs Kiss, US diver Harrison Jones and US hammer thrower Thomas Freeman.
The International Association of Athletics Federations said the decision will impact an estimated 50 track and field athletes hoping to compete in London.
''The IOC has a zero tolerance against doping and has shown and continues to show its determination to catch cheats,'' the committee said in a statement. ''We are therefore naturally disappointed since the measure was originally adopted to support the values that underpin the Olympic movement and to protect the huge majority of athletes who compete fairly.
''The rule was in our view an efficient means to advance the fight against doping, and we were somewhat surprised by the judgment since we had taken an advisory opinion from CAS on the rule and been given a positive response.''
The verdict against the IOC also opens the door for athletes in Britain to challenge a British Olympic Association rule that bans drug offenders for life from the games.
Among those affected by the British ban are sprinter Dwain Chambers, a former European 100-meter champion who served a two-year ban in the BALCO scandal, and cyclist David Millar, who also was suspended for two years for use of EPO.
Millar called the CAS ruling a ''good thing for future of international sport.''
''Only a matter of time till all countries respect WADA Code,'' he tweeted.
CAS, which is based in Lausanne, Switzerland, said the IOC could propose an amendment to the WADA code that would mean the rule would be ''part of a single sanction.''
''When the moment comes for the revision of the World Anti-Doping Code we will ensure that tougher sanctions, including such a rule, will be seriously considered,'' the IOC said in its statement.
Blackmun thanked the IOC for agreeing to take part in the arbitration.
''We completely support the IOC in their efforts to have stringent anti-doping sanctions,'' he said. ''It's just that this case created uncertainty for our athletes. This was a mutual decision to get some clarity.''
The USOC and IOC went to CAS to seek a ruling well ahead of the London Games to avoid last-minute confusion before the Olympics start on July 27, 2012. An eight-hour hearing was held in Lausanne on Aug. 17.
Among those supporting the USOC in the court case were the US Anti-Doping Agency and anti-doping bodies in Britain, Denmark, Norway, New Zealand, Japan and South Africa.
The IOC's rule — known as Rule 45 — took effect in 2008, just ahead of the Beijing Games, but London would have been the first Summer Olympics fully covered by it.
Merritt, who was also 400-meter world champion in 2009, received a 21-month suspension last year after testing positive.
His penalty was reduced from the usual two-year suspension because he cooperated with authorities and was found to not have taken the drug to enhance athletic performance.
Merritt's ban expired in July and he returned to international competition, including the world championships in Daegu, South Korea. He finished second in the 400, overtaken down the stretch by Kirani James of Grenada, but helped the Americans win gold in the 1,600-meter relay.
The American Arbitration Association panel, which banned Merritt, said the IOC rule went against the World Anti-Doping Agency code and would essentially extend his ban to three years.
''We do not believe that the CAS decision will have any adverse impact on the anti-doping movement,'' IAAF spokesman Nick Davies said, noting that sports bodies still have the ability to impose four-year suspensions in serious cases.
