This year's Tour de France, which began on Saturday, is a prodigious test. Not just for the riders who climb, sprint and sweat their way along the three-week, 2,270-mile journey across the Alps and countryside. It's also a prodigious test for cycling's future. After seven straight victories, Lance Armstrong is no longer competing. Yet his legacy of success--coupled with fresh allegations of his wrongdoing--is casting a shadow over the start of this year's already chaotic race.
Critics, particularly in France, have long accused Armstrong, a cancer survivor, of needing drugs to win his titles. Adding fuel to that fire is recent...