In the future, perhaps all sports record books should carry an asterisk on the cover.

Many fans have long suspected that steroids were pumping up some of baseball’s most prolific sluggers. Last week’s revelation that the New York Yankees’ Jason Giambi had admitted as much to a grand jury was followed by even more damaging news: Barry Bonds, who stands on the threshold of breaking Henry Aaron’s record for career home runs, told the same grand jury that he had used substances that he didn’t think were steroids – though it appears likely that they were.

Whether Bonds was being truthful about his own knowledge is almost beside the point. Baseball has been severely damaged, as track and field has been over similar revelations.

There’s no quick way to heal these wounds. They might even get worse as more details emerge. Nonetheless, the sport must begin immediately by taking dramatic steps to restore its own credibility. The first step should be taken by the players union, which has impeded efforts by baseball’s hierarchy to rid the game of performance-enhancing drugs.

The union must come to grips with the seriousness of this problem, both for the image of its members and their own safety. Only by agreeing to baseball’s demands for comprehensive testing and tough sanctions against steroid users will the union show that it doesn’t tacitly approve such cheating. It’s outrageous that the union hasn’t already done so just to protect players from steroids’ life-threatening side effects.

And all this says nothing of setting a responsible example for youngsters who idolize – and emulate – professional athletes.

How many of Barry Bonds’ 703 home runs were aided by steroids? Some? Most? None? We may never know, but we’ll always question the legitimacy of his records. Similarly, this scandal casts a shadow on other baseball records, as well as those in other sports.

The leaders of all sports, and their athletes, must make a mission of getting performance-enhancing drugs out of their arenas. Zero-tolerance must be the rule, as it is with gambling.

Without certainty that athletic competition is on the up-and-up, results and records are meaningless. Meaningless games won’t sell many tickets.