Claire Beale on Advertising: Big brands pay up big to bask in a star's success

You'd think a marketer as savvy as Nike would know better. When your brand spokesman hits the headlines for all the wrong reasons, think carefully – very carefully – before you insist you're standing by him.

But when the Nike-sponsored cyclist Lance Armstrong was charged with drug-taking by the United States Anti-Doping Authority, the sportswear giant wasted no time posting a statement that "Nike plans to continue to support Lance". The Swoosh, it seemed, was sticking firmly to its man.

Well, for a few days at least. Because less than a week later Nike made an embarrassing U-turn, deciding it didn't, after all, plan to continue supporting Lance, and summarily terminated its contract with the cyclist "due to the seemingly insurmountable evidence that Lance Armstrong participated in doping and misled Nike for more than a decade".

The advertising history books are bulging with cautionary tales of celebrity endorsements. Big brands pay big bucks to bask in the reflected glory of celebrity, buying into a star's aura of glamorous success. As soon as the star turns sour, the brand risks being associated with all the negativity that ensues. Really, once your star is tarnished the safest course is to peddle as fast as possible in the opposite direction.

It's perhaps honorable for Nike to have stuck with Armstrong until the evidence became so overwhelming; honorable or shrewd. Nike's stood by many of its scandal-hit celebrity endorsers in the past – Tiger Woods, Kobe Bryant and scores of others – and the partnerships have continued to work well for Nike after the drama has quieted.

But loyalty to Armstrong would have taken Nike into a whole new cycle lane; where stars like Woods and Michael Jordan courted controversy away from their sport, Armstrong stands accused of cheating his way into sporting superstardom and that's hardly an aura a brand built on enhancing performance wants to hook its fortunes to.

So why did the usually sure-footed Nike stumble over this one, initially supporting the disgraced cyclist? Most likely it was hoping to sever its ties with Armstrong quietly, away from the media spotlight once the reporting pack had moved on.

In the end though, the damage to Armstrong's sporting reputation was so severe it threatened to drag Nike down too. And even the world's most valuable sports brand – $15.9bn and growing – can't afford that.

Claire Beale is editor of Campaign