Toward the end of the first Democratic debate last week, the moderator, Anderson Cooper, brought up the topic of marijuana with a joke. “Some of the candidates have tried marijuana, as have pretty much — probably everybody in this room,” he said. The largely white, upper-middle-class audience laughed. Of course they had.

Marijuana is by far the most ubiquitous illegal drug in the United States: 49 percent of Americans have tried pot at least once, and more than a quarter of Americans under 30 have smoked up in the last month. If the aim of keeping marijuana illegal is to make it unavailable and discourage people from using it, it’s hard to think of a policy that has failed more miserably. Tens of millions Americans, including the last three presidents, have smoked pot, and it is widely and correctly viewed as benign. So it’s not surprising that Cooper got a bit of a chuckle for accusing everyone in the room of committing a crime.

In response, the Democratic front-runner, Hillary Clinton, came out against the legalization of marijuana. She made a brazen attempt to have it both ways, calling for “more research” and suggesting that marijuana should remain illegal but that no one should go to prison for it — an endearing paradox reminiscent of Bill Clinton’s 1992 claim that he smoked marijuana but “didn’t inhale.” But evasions aside, she wants to keep weed criminalized. Presidential candidates don’t typically tell an audience that half the people in it should be arrested and given permanent criminal records, yet that’s what happened. So why wasn’t she booed off the stage?

If you’re a white middle-class American, as most of Clinton’s audience was, your odds of facing legal consequences for marijuana possession are vanishingly small. You won’t be caught, you won’t be arrested, and if you are arrested you’ll get a slap on the wrist. The same goes for your children and your friends and your stoner nephew: You’ll all be fine.

That’s why, although a majority of Americans favor legalization (53 percent, including 68 percent of millennials), it hasn’t become a major political issue: White Americans see it as a matter of cultural politics rather than criminal justice policy — a way of signaling what side you’re on in the culture wars rather than a decision about who should be locked up.

That’s dead wrong. According to the ACLU, there were 8.2 million arrests for marijuana in the U.S. from 2001 to 2010 — hundreds of thousands a year, 88 percent of them just for possession. So why don’t most Americans care? How is it possible for a presidential candidate who calls herself progressive to stay on the wrong side of this issue?