The arguments for legalizing marijuana for consenting adults have all been heard.

Let’s look at one of the biggest arguments against legalization: That it poses a threat to public safety and our youth.

The major argument against legal marijuana — as it has been since being erroneously labeled a “gateway drug” — is that it would signal moral permissiveness, create an increased prevalence, and make it easier for young people to obtain. Doomsayers add this issue to recent voter approvals of casino gambling and same-sex marriage to presage some vast decline in civilization that will destroy society at large.

Forget for the moment all these issues had broad bipartisan support. Liberals and conservatives alike endorse the idea of personal liberty, that people can decide for themselves what is best. Maine Republicans endorsed gay marriage in substantial numbers, and we’re seeing this again in the number and type of cosponsors of a recent bill to legalize and tax marijuana. Casinos have been seen as a net positive. In all these issues, what’s good for freedom also happens to be good for the Maine economy, which is probably why they’ve enjoyed bipartisan support.

The U.S. prison population is six to 10 times as large as most western European nations, and a close second to Russia in its rate of incarceration per 100,000 people. Yet more than 829,000 Americans were arrested for marijuana-related offenses in 2006, according to the National Organization for the Reform of Marijuana Laws. While drunken driving killed 10,000 people in 2011, and that substance remains entrenched in our social fabric, marijuana — with hardly any known fatalities by motor vehicle, overdose or any other manner — remains illegal, and expensively so.

High-cost enforcement, low-risk behavior.

Maybe that’s why the voice of law enforcement in the debate over decriminalizing marijuana has been rather muted.

Could it be that they are actually on board with the idea?

After all, with estimates of $2 billion to $7 billion spent enforcing prohibition nationally, with thousands of hours patrolling skies to parking lots in search of everything from plantations to petty users, is it possible this police power could be better spent elsewhere? We’ll bet we could find a few highprofile police in Maine to say yes, it is.

Could it be law enforcement believes in privatizing the enforcement regime for marijuana? After all, business and law enforcement have been effective partners placing effective controls on the sale of controlled substances, from alcohol to cough medicine. It’s rather easy. You put the stuff behind a counter and ask for positive ID. No ID, no product. Fake ID, get arrested.

With such a regime already in place, legalization would likely make it harder for youths to obtain pot, because — as supply increases, prices fall and legal outlets expand — the black market shrinks, and minors find fewer illegal, unregulated outlets to obtain it.

Isn’t a taxed, legal, controlled product better than worrying about what could happen during a street deal gone wrong? What say you, parents? Police?

Isn’t that better than paying billions for the helicopter, the boots on the ground seizing plants, the jail space for incarcerated users, the public defenders and prosecutors?

We won’t get into the positive revenue effect of decriminalization. Reducing enforcement costs and increasing tax revenues sounds like a winner to us, especially if the public safety piece works, as we believe we have demonstrated it could.

Unless you believe that marijuana — like gambling, like gay people — is just going to disappear someday, doesn’t it sound more rational to regulate these adult behaviors — not prohibit them — so those who abhor it can avoid it while those who partake can freely enjoy it?

That’s what liberty looks like from here.