Any law disobeyed by more than 100 million Americans, the number who’ve tried marijuana at least once, is bad public policy. As a 34-year police veteran, I’ve seen how marijuana prohibition breeds disrespect for the law, and contempt for those who enforce it.

Let’s examine arguments against legalizing marijuana: use and abuse would skyrocket; the increased potency of today’s marijuana would exacerbate social and medical problems; and legalization would send the wrong message to our children.

It’s reasonable to expect a certain percentage of adults, respectful or fearful of the current prohibition, would give pot a first try if it were made legal. But, given that the U.S. is already the world’s leading per capita marijuana consumer (despite our relatively harsh penalties), it’s hard to imagine a large and lasting surge in consumption. Further, under a system of regulated legalization and taxation, the government would be in a position to offer both prevention programs and medical treatment and counseling for those currently abusing the drug. It’s even possible we’d see an actual reduction in use and abuse, just as we’ve halved tobacco consumption through public education — without a single arrest.

Potency? Users, benefiting from the immutable law of supply and demand, have created huge market pressure for “quality” marijuana over the past few decades. Legalization opponents are correct that “today’s weed is not your old man’s weed.” But the fear-mongers miss the point, namely that stronger strains of marijuana are already out there, unregulated by anything other than market forces. It’s good that responsible consumers know to calibrate their consumption; they simply smoke less of the more powerful stuff. But how about a little help from their government? Purchase booze and you have access, by law, to information on the alcoholic content of your beverage, whether it’s .05 percent near-beer or 151-proof Everclear.

Perhaps the biggest objection to legalization is the “message” it would send to our kids. Bulletin: Our children have never had greater access to marijuana; it’s easier for them to score pot than a six-pack of Coors. No system of regulated legalization would be complete without rigorous enforcement of criminal laws banning the furnishing of any drug to a minor.

Let’s make policy that helps, not handcuffs, those who suffer ill effects of marijuana or other drugs, a policy that crushes the illegal market — the cause of so much violence and harm to users and non-users alike.

Norm Stamper was Seattle’s police chief from 1994 to 2000. He is a member of Law Enforcement Against Prohibition and the author of “Breaking Rank: A Top Cop’s Exposé of the Dark Side of American Policing.”