Thank goodness for the phenomenon that is Michael Phelps. His haul of eight gold medals is all that is saving the United States’ performance at the Beijing Olympics from being disappointingly lackluster.

Although the U.S. holds the most medals overall, at least for now, China is winning the gold rush 39 to 22. Phelps’ eight account for an amazing 36 percent of America’s gold tally.

Of course, he didn’t do it by himself. Three of his medals were in relays in which he needed other swimmers to swim their best, too. And they did, helping him set seven world records and enabling him to lay claim to winning the most gold medals in a single Olympics, eclipsing Mark Spitz’s seven.

Phelps’ record medal haul could stand a long time, because an athlete of his caliber is a rarity. Or it might fall in 2012; he says he’ll compete at the London Olympics and substitute one or more shorter races for the grueling 400 individual medley. In the interim, his plate will be full with endorsement opportunities that some in the business say could bring him up to $40 million in the next few years.

“I’m not doing it for the money,” he has said. “I’m doing it because I love what I do.” Talking like that will only endear him more to the folks who hope to hitch their commercial star to his.

Phelps has showed good sportsmanship and unabashed devotion to his mother, Debbie, who raised him and his sisters by herself in suburban Baltimore. The sight of him running into the stands to celebrate with her after his eighth win warmed mothers’ hearts all over the world. It hasn’t been all smooth sailing for Phelps; there was that 2004 DUI, after all, but that’s all been forgotten in the glow of eight gold medals.

Phelps has said that he wants to be an ambassador for swimming in the way Michael Jordan was for basketball and Tiger Woods is for golf. If he can be only half as good at that as he’s been at these Olympic games, kids will be jumping into pools all over America.