On Monday, after Richland County, S.C., Sheriff Leon Lott announced that he did not have enough evidence to arrest Olympic swimmer Michael Phelps for smoking marijuana at a November party in Columbia, the gold medalist issued a statement of regret. "I used bad judgment, and it's a mistake I won't make again," Phelps said. "For young people especially -- be careful about the decisions you make. One bad decision can really hurt you and the people you care about."

Phelps' mistake was not smoking pot so much as doing it in front of someone with a cell phone camera and no compunction about selling the picture to a British tabloid. And if that mistake hurt him, it's not because marijuana turned the record-breaking champion into a slacker or a drug addict. It's because consuming an arbitrarily proscribed intoxicant can result in serious legal (and therefore social and economic) consequences, which cause far more harm than marijuana itself.

This reality should be recognized by President Obama, whose own youthful pot smoking did not exactly hold him back but whose future might have been very different if he had been arrested on drug charges in high school or college. The same, of course, could be said for the two drug-experienced baby boomers who preceded him in the White House. But there are some indications that Obama may take a less dogmatic approach to drug policy.

A few days after that photo of Phelps sucking on a bong appeared in the News of the World, the Obama administration signaled that the president will keep his campaign promise to stop the Drug Enforcement Administration's raids on medical marijuana dispensaries, five of which have occurred since he took office. "The president believes that federal resources should not be used to circumvent state laws," a White House spokesman told The Washington Times, "and as he continues to appoint senior leadership to fill out the ranks of the federal government, he expects them to review their policies with that in mind."

The week after Lott's deputies, looking for evidence to incriminate Phelps, raided two houses and charged seven people with marijuana possession, newspapers reported that Obama had chosen Seattle Police Chief Gil Kerlikowske to head the Office of National Drug Control Policy. Kerlikowske is known for decidedly milder treatment of pot smokers than the hard-line sheriff, who said investigating Phelps was necessary to avoid "sending a message of tolerance."

Norm Stamper, who preceded Kerlikowske as Seattle's police chief and now promotes drug policy reform as a member of Law Enforcement Against Prohibition, said the "one thing I know for sure" about Kerlikowske is that "if Michael Phelps had bent over that bong in Seattle and not in Sheriff Leon Lott's Richland County he'd have nothing to fear but a foolish and fickle cereal maker" (a reference to the widely criticized decision by Kellogg's to drop its endorsement deal with Phelps). Although Kerlikowske's personal views on drug policy are unknown, he has helped implement state and local reforms such as allowing medical use of marijuana and making pot possession Seattle's "lowest law enforcement priority."

Among other things, the latter policy means police can patrol Seattle's annual Hempfest, where the scent of burning cannabis is conspicuous, without arresting every other person. It is hard to imagine Lott exercising similar restraint.

If you're glad that police arrested a record 873,000 Americans on marijuana charges in 2007 (the vast majority of them for simple possession), you can thank zero-tolerance zealots like Lott. The sheriff said he felt compelled to investigate Phelps, which involved busting seven people directly or indirectly linked to the party he attended, to show that "even with his star status, he is still obligated to obey the laws of our state." In the end, though, this case worked out the way drug cases usually do: The big shot got off, and the little guys got shafted.