The U.S. Anti-Doping Agency plans to strip cyclist Lance Armstrong of his unprecedented seven Tour de France titles and ban him for life.The harsh punitive measure follows Armstrong’s decision drop the fights against the drug charges that have followed him for years and figures to tarnish his legacy as one of the sport’s greatest ever.Armstrong, who retired last year, declined to enter USADA’s arbitration process because he had simply grown tired of the allegations of cheating that have dogged him for years. He has consistently pointed to the hundreds of drug tests he passed over the years as proof of his innocence while winning Tour titles from 1999-2005.“There comes a point in every man’s life when he has to say, ‘Enough is enough.’ ,” he said Thursday. “For me, that time is now.”Armstrong called the USADA investigation an “unconstitutional witch hunt.”“I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999,”he said. “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.”USADA reacted quickly, treating Armstrong’s decision as an admission of guilt before saddling him with the label of cheater. Under the World Doping Code, Armstrong could also lose other awards, event titles and cash earnings, while the International Olympic Committee could possibly look at revoking the bronze medal he won at the 2000 Sydney Olympics.USADA contends that Armstrong has used banned substances as far back as 1996, including the blood-booster EPO and steroids, as well as blood transfusions to boost his performance.Armstrong walked away from the sport in 2011 without being charged following a two-year federal investigation into many of the same accusations he faces from USADA. The federal probe was closed in January, but USADA announced in June that it had its own evidence of Armstrong’s wrong-doing. The agency also claimed it had 10 of Armstrong’s former U.S. Postal Service teammates who were ready to testify against him.Armstrong became a household name in America after his Tour wins and storied comeback from testicular cancer and helped lift the sport to unprecedented popularity.Created in 2000, USADA is recognized by Congress as the official anti-doping agency for Olympic sports in the United States.