American public opinion has been gradually shifting on the question of legalizing marijuana. In the last couple of years, the proportion of the country in support has reached critical mass: In a Gallup poll released Wednesday, fully 64 percent of Americans support legalization — including a majority of Republicans.

It's in many ways quite similar to what happened with gay marriage. However, unlike when the gay marriage public opinion wave started to crest in 2012 and 2013, as of yet few high-profile Democrats have come out for legalization. It's long since time the party came around on this issue — not just on policy or political grounds, but to get out ahead of a more corporate legalization approach.

Now, there are some exceptions, most prominently Sen. Cory Booker (D-N.J.), who to his credit introduced a bill to legalize marijuana at the federal level in August. In fact, Booker's bill is considerably more aggressive than even Bernie Sanders' bill from 2015, which would have merely allowed states to legalize marijuana — thus formalizing the quasi-legal status of the eight states and D.C. that have legalized marijuana to varying extents. In comparison, Booker's bill would remove marijuana from the Controlled Substances Act, pressure states into legalizing it, expunge federal marijuana use and possession crimes, allow marijuana convicts in federal prison to petition for resentencing, and create a community reinvestment fund to rebuild places hit hardest by the war on drugs.

It's a great start. The war on drugs is an abject failure, and it's long since time we treated marijuana more sensibly.

It is honestly rather baffling that more Democrats haven't seized on this. There are few if any political issues with 64 percent support lying around for the taking — especially not ones that are guaranteed to receive little or no Republican support. The political case is further strengthened by the history of 2016, where Hillary Clinton — who refused to support legalization — hemorrhaged critical swing-state votes to the Green Party's Jill Stein and the Libertarian Party's Gary Johnson.

If there's a better or easier way to sell yourself to hippies and libertarians at the same time than legal weed, I certainly haven't heard of it.

But policy matters a lot here too. Marijuana is one of the least dangerous drugs, but it is a drug, and selling drugs like a normal commodity is highly non-ideal. Just like gambling or alcohol, a large bulk of marijuana use tends to come from a tiny minority of users. A large corporation will thus be incentivized to get as many heavy users hooked as early in life as possible and spending as much as possible, by advertising to children and selling cheap Bud Lite-style pot in bulk.

Therefore, a federal marijuana legalization scheme should have sharp regulations on the sale of marijuana, with the deliberate intention of keeping it a small, craft business. That means stuff like very high taxes, to keep prices high (though not so high as to recreate a black market) and use down; a total ban on all advertising; a ban on selling across state lines; and a ban on any business accumulating more than, say, 10 percent of the total marijuana sales in any single state, or 1 percent of the national market, whichever is smaller.

The ideal future would be a lot of artisanal growers selling umpteen zillion different varieties of high-quality craft weed to a population of relatively moderate users — not a future of Big Pot selling bale-sized bags to brain-fried potheads. There will be some people who use too much, of course — but that can't really be helped, given that there are quite a few such people today under prohibition.

This would have the knock-on possibility of helping staunch the opioid crisis. Marijuana's possibilities as a pain reliever are still being explored, but it has shown a ton of promise. It's quite likely that a great many people using opioids for pain relief could instead be prescribed pot — and while it is possible to abuse pot, it is approximately one-thousandth as dangerous as oxycodone, and one-millionth as dangerous as fentanyl. Not only is it far less addictive, it is literally impossible to overdose and die — there has never been a single case of a fatal marijuana overdose in recorded history. If it's possible to displace opioids in this area, it would be a huge public health triumph.

But the best potential effects of all would be on crime and violence — much of it south of the border. Illegal marijuana trafficking is a big profit center for gangs and drug cartels, whose violent conflicts with each other and the governments of Mexico, Honduras, El Salvador, and others, have killed tens of thousands of people (though less than it used to be given the spread of legalization and medical marijuana laws). Preliminary studies suggest that the spread of more legal ways to obtain marijuana has resulted in moderate drops in violent crime — especially in southern border states.

It wouldn't abolish the cartels at a stroke, of course — for that you'd probably have to decriminalize harder drugs like heroin and meth, but that's a subject for another post.

All in all, it's a total policy gimme: Claim the political high ground, lay in a new source of significant tax revenue, slow the opioid epidemic, and strike a blow against crime. Democrats need to ditch their inner Nancy Reagan and pick up the political bong.