Last year voters in Colorado and Washington approved ballot measures legalizing recreational marijuana use. Last week Colorado approved another measure that imposes a 15 percent excise tax and a 10 percent retail tax on pot. Portland, Maine, also passed a measure legalizing weed. So did three more Michigan cities (bringing the total there to five).

Virginia should, too. Here are five reasons why.

(1) It's none of the government's business. Consider: "Marijuana prohibition is perhaps the oldest and most persistent nanny-state law we have in the U.S. We simply cannot afford a government that tries to save people from themselves. It is not the role of government to try to correct bad behavior, as long as those behaviors are not directly causing physical harm to others." Those are not the words of some San Fran hippie holdover with love beads and a Seventies-vintage VW bus. They come from former Sen. Tom Tancredo of Colorado, a Republican with a lifetime rating from the American Conservative Union of 99 percent.

Tancredo's point is one with which liberals ought to agree. Shortly before the election Tarina Keene, director of NARAL Pro-Choice Virginia, said Terry McAuliffe would owe his victory to women "who want to own their own bodies." If you agree with the concept of self-ownership, then you should agree with Milton Friedman: "I don't think the state has any more right to tell me what to put into my mouth than it has to tell me what can come out of my mouth."

(2) Pot prohibition is unnecessary. Federal law classifies marijuana as a Schedule I drug, along with heroin and LSD. According to the Justice Department, Schedule I drugs are "the most dangerous drugs of all the drug schedules," with "no currently accepted medical use" and "potentially severe psychological or physical dependence." This is absurd. True, chronic pot use is bad for you. But people chronically — and legally — use many things that are bad for you. If the harm threshold necessitating prohibition is set by laws governing tobacco and alcohol, then marijuana, which is no worse than they are, should be treated like they are. If it is not necessary to forbid something, then it is necessary not to forbid it.

(3) Prohibition costs a gawd-awful lot. America spends $3.6 billion a year enforcing its pot laws — $245 million of that here in Virginia. Arrests for possession have risen from 260,000 in 1990 to 750,000 in 2010; a whopping 10 million Americans have been arrested for possession in the past 15 years. And a fat lot of good it has done: Nearly half of U.S. adults have tried pot at least once; the National Institute on Drug Abuse says more than 17 million Americans have used it within the past month.

(4) Prohibition disproportionately hurts minorities. Whites and blacks smoke weed in roughly equal proportions, but blacks are far more likely to be arrested for possession. According to a recent piece in The Nation, police in major cities arrest blacks for marijuana possession at seven times the rate for whites. Many of those busted are young: Nationwide, 62 percent are 24 or younger.

Why the big racial disparity? Not because cops are racist. Rather, police tend to patrol high-crime areas, which mean low-income areas populated by minorities. When officers stop someone in those areas, they search for contraband — and often find pot.

They might find it in rich white neighborhoods, too, but "police officers patrolling in middle- and upper-middle-class neighborhoods typically do not search the vehicles and pockets of white people, so most well-off whites enjoy a de facto legalization of marijuana possession."

That racial disparity perpetuates others, including economic disparity. A criminal record makes getting a job harder, and spending time behind bars impedes wealth accumulation. Legalizing marijuana would change all these dynamics, starting at the source: Frequent, low-level drug busts can contribute to statistics that designate an area as "high-crime" and subject it to increased police scrutiny.

(5) The state is cutting off its own nose to spite its face. As Tancredo noted in his 2012 op/ed column in the Colorado Springs Gazette, prohibition does not stop marijuana use; it merely ensures "that all of the profits from the sale of marijuana … flow to the criminal underground." Meanwhile, taxpayers foot exorbitant enforcement bills. By contrast, estimates of the revenue from Colorado's newly approved taxes ranges from $40 million to more than $130 million a year. Those figures include only direct proceeds from excise and sales taxes. But other indirect proceeds could add up as more of the marijuana industry moves into the stream of legal commerce. Bootleggers don't pay income tax, but beer distributors do.

Virginia has a lot to gain from bringing marijuana out of the shadows, but doing so will be a long slog; at the Virginia General Assembly, even money doesn't always have the final word. Last year Del. David Englin introduced a bill merely to study the revenue potential from pot legalization. It was killed in subcommittee by anonymous vote.

This column originally appeared in the Richmond Times-Dispatch.