Though the hazy spectacle pot smokers created Monday — and that they create each April 20 at 4:20 p.m. — grabbed some media attention, it probably did little to advance their cause of legalizing marijuana.

This country has waged an expensive and ineffective “war on drugs,” including marijuana, for decades, and it’s high time (to rather predictably borrow a phrase) that the debate on whether to decriminalize cannabis reached the halls of Congress.

Interestingly, it’s not just the dope smokers in the park calling for legalized marijuana use. Conservative, progressive and libertarian intellectuals alike have argued that we ought to legalize marijuana. The Post’s editorial board has long called for an end to the war on pot.

Our opinion meshes, in this instance, with that of the late conservative writer William F. Buckley Jr., who once argued that “the government should treat marijuana more or less the same way it treats alcohol: It should regulate it, control it, tax it, and make it illegal only for children.”

President Barack Obama has requested more than $14 billion to fund the drug war at the federal level in 2009. State and local enforcement costs drive that figure far higher.

Year after year, a few hundred thousand people end up in court and prison as a result of drug crimes. Our overcrowded prisons are just one reason to take another look at some of our drug laws.

Granted, there are still many dangerous drugs out there. Highly addictive drugs like methamphetamine or crack cocaine swept through our nation’s cities and suburbs and rural communities like epidemics.

But legions of studies have shown that marijuana isn’t addictive.

And as recent U.S. presidents have shown, use of the drug, even when inhaled, doesn’t in and of itself ruin a person’s chance at achieving full and productive lives. Yes, pot users face risks as potentially as devastating as other drugs. So do drinkers of wine and beer.

But regulating the drug, as alcoholic beverages are regulated, can provide for prevention and therapy, while also starving the criminal element from this cash stream.

Marijuana also could be taxed, with the money earmarked to fund treatment programs for victims of truly dangerous drugs.

We did not support the successful effort to legalize minor marijuana possession in Denver, and we have not supported statewide ballot efforts to legalize the drug. The problem with local laws is that they conflict with federal laws and create legal headaches that further muck up the courts and jam prisons.

But our elected federal representatives could change all that. And they should.