Famed cyclist Lance Armstrong is facing the loss of seven Tour de France titles and his championship legacy after ending his fight against charges of illegal doping.
Armstrong's move prompted the U.S. Anti-Doping Agency on Friday to slap a lifetime ban on the athlete and strip him of his wins dating to 1998, though there is a question of whether the organization has the authority to take such action.
"If I thought for one moment that by participating in USADA's process I could confront these allegations in a fair setting and -- once and for all -- put these charges to rest, I would jump at the chance," Armstrong said in a statement Thursday.
"I refuse to participate in a process that is so one-sided and unfair."
The World Anti-Doping Agency and the International Cycling Union will review the USADA's findings, with one or both agencies then given the option to appeal the case before Armstrong can be banned or stripped of titles.
Armstrong has vehemently denied U.S. Anti-Doping Agency allegations that he took steroids throughout his career. The agency said it has testimony from former teammates to support the charges, though it has declined to reveal who provided the evidence.
The International Cycling Union, which Armstrong has said should be the arbiter of his case, has previously opposed the USADA actions by claiming it has jurisdiction. That position has been recently backed by USA Cycling, the official cycling organization recognized by the U.S. Olympic Committee.
But the U.S. agency said the anti-doping regulations that Armstrong is being sanctioned for are defined as violations by the cycling union and other agencies, all of which have adopted the World Anti-Doping Code and the WADA's prohibited list.
The International Cycling Union said Friday it will not comment on the case until the USADA issues "a reasoned decision" explaining its stance.
The cycling union has 21 days to file an appeal following a review of the USADA case, and then the World Anti-Doping Agency can file its own appeal, said Terence O'Rorke, a spokesman for the WADA.
The World Anti-Doping Agency's president, John Fahey, said on Australian radio that the allegations against Armstrong have credibility. He said he is disappointed the case would not be tested because of Armstrong's decision not to challenge the charges.
The U.S. agency has charged Armstrong with using, possessing, trafficking and giving to others performance-enhancing drugs, as well as covering up doping violations.
"Nobody wins when an athlete decides to cheat with dangerous performance-enhancing drugs, but clean athletes at every level expect those of us here on their behalf to pursue the truth to ensure the win-at-all-cost culture does not permanently overtake fair, honest competition" said U.S. Anti-Doping Agency CEO Travis Tygart.
"Any time we have overwhelming proof of doping, our mandate is to initiate the case through the process and see it to conclusion, as was done in this case."
Armstrong has been an icon for his feats and celebrity, bringing more status to a sport wildly popular in some nations but lacking big-name recognition, big money and mass appeal in the United States.
He fought back from testicular cancer to win the Tour from 1999 to 2005. He raised millions via his Lance Armstrong Foundation to help cancer victims and survivors, an effort illustrated by trendy yellow "LiveSTRONG" wristbands that helped bring in the money.
The cyclist's one-time high-profile relationship with singer Sheryl Crow also kept him in the public eye.
But Armstrong has been dogged by doping allegations in recent years, with compatriot Floyd Landis -- who was stripped of his 2006 Tour de France title after failing a drug test -- making a series of claims last year.
Armstrong sued the U.S. Anti-Doping Agency to stop its investigation of him, arguing it did not have the right to prosecute him.
But a federal judge Monday dismissed Armstrong's lawsuit after ruling the court did not have jurisdiction.
After that ruling, Armstrong said "enough is enough" in the face of his battle with the USADA and Tygart, whose investigation he describes as a farce. The U.S. agency is the official anti-doping agency for Olympic, Pan American and Paralympic sports in the United States.
"I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999," Armstrong said. Over the past three years, I have been subjected to a two-year federal criminal investigation followed by Travis Tygart's unconstitutional witch hunt. The toll this has taken on my family, and my work for our foundation and on me leads me to where I am today -- finished with this nonsense."
Armstrong said he plans to help people "affected by cancer" and is "looking forward to an end to this pointless distraction."
"Today I turn the page. I will no longer address this issue, regardless of the circumstances," he said "I have a responsibility to all those who have stepped forward to devote their time and energy to the cancer cause. I will not stop fighting for that mission. Going forward, I am going to devote myself to raising my five beautiful (and energetic) kids, fighting cancer, and attempting to be the fittest 40-year old on the planet."
Armstrong came out fighting in May 2011, in the face of fresh allegations made on CBS News' "60 Minutes" show by another American, Tyler Hamilton.

