He overcame testicular cancer to win seven consecutive Tour de France titles, but the indefatigable Lance Armstrong is abandoning the fight to clear his name of doping charges. Armstrong announced late last night that he will stop fighting allegations by the U.S. Anti-Doping Agency (USADA) that he used banned substances (read our primer on the complete charges) throughout his career. USADA replied immediately, saying it would ban Armstrong from competition for life and recommend he be stripped of his unprecedented seven Tour de France titles.

"There comes a point in every man’s life when he has to say, 'Enough is enough,'" the Texan said in a statement. "For me, that time is now." This comes just days after a federal judge dismissed Armstrong's lawsuit intended to halt the USADA's drug case against him. Without hope of federal intervention, Armstrong saw no point in participating in what he considered a deeply unjust court battle, despite the possibility of forever clearing his name. "If I thought for one moment that by partcipating 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," he said. "But I refuse to participate in a process that is so one-sided and unfair."

"It is a sad day for all of us who love sport and our athletic heroes," USADA chief Travis Tygart said. "This is a heartbreaking example of how the win-at-all-costs culture of sport, if left unchecked, will overtake fair, safe and honest competition." Armstrong, for his part, accuses Tygart of leading an "unconstitutional witch hunt" against him and maintains that USADA has no jurisdiction over his case. And, to some extent, he's right, at least as far as his Tour titles are concerned. Those are now in the hands of the International Cycling Union (UCI), the sport's worldwide governing body, which plans to examine the USADA's evidence before they make any decisions.

Naturally, news of this magnitude has been met with mixed reactions from news pundits, media and the cycling community. Here are highlights from what we've read:

• Velonews.com spoke with a handful of big names in the cycling world. Highlights: Five-time Tour de France champion Bernard Hinault says, "I couldn't give a damn."; Legendary cyclist Eddy "The Cannibal" Merckx backs Lance up, saying, "Lance was always very correct during his career. What more can he do? All the tests he’s undertaken, more than 500 since 2000, have come back negative. So, either the tests don’t count for anything, or Armstrong is legit."; 1988 Tour winner Pedro Delgado says, "It’s bad news for cycling, and we know that the victims are always cyclists.”
• The Guardian's The Sport Blog guns for "the man who strong-armed cycling," with this summary graph: "By refusing to mount a defence in the US Anti-Doping Agency's case against him, Lance Armstrong has—whatever equivocation and claims of persecution he persists in—all but conceded that he won his seven Tour de France titles by doping. And by walking away from a defence he has ceded those yellow jerseys and lost his status as the most remarkable serial winner in the history of the sport."
• Reuters quoted World Anti-Doping Agency (WADA) chief John Fahey saying, "There can be no other interpretation. To refuse the charges can only leave the interpretation that [Armstrong] is a cheat." Also, he says Armstrong's Tour titles should be "obliterated."
• The New York Daily News' Mike Lupica compares Armstrong to sports' biggest cheaters, including Marion Jones and baseball's juiced-up sluggers, and points out that, in the end, the lying is worse than the cheating itself. He also talks about Armstrong's bullying tactics, and points out that, if his Tour titles are stripped, Greg LeMond will be the only American to have officially won a Tour de France. Sad.
• ESPN's Bonnie Ford is in disbelief over Armstrong's backing down. In her article, "Surprising end for an epic fighter," she talks about the worst outcome for Lance, the fierce competitor: "The real penalty and the starkest shift in Armstrong's landscape is the lifetime ban from competition in, or even association with, the endurance events that consumed him and molded his public persona."
• Sports Illustrated's Michael Rosenberg says that maybe Americans don’t really care whether Armstrong used drugs, but they do care—and don't like it—if he lied to them.