With his final election behind him, and the final attack ads safely off the air, President Obama now returns to his regularly scheduled programming — governing. Yet, the chatter about his second term agenda, from deficit reduction to immigration reform, ignores one critical issue: ending our nation’s inhumane, irrational — and ineffective — war on drugs.

Since its launch in 1971, when President Nixon successfully branded drug addicts as criminals, the war on drugs has resulted in 45 million arrests and destroyed countless families. The result of this trillion dollar crusade? Americans aren’t drug free — we’re just the world’s most incarcerated population. We make China look like Woodstock. We’re also, according to the old definition, insane; despite overwhelming evidence of its failure, our elected officials steadfastly refuse to change course.

But on November 6, citizens in Colorado and Washington became the first to approve ballot initiatives legalizing the recreational use of marijuana. Their success illustrates growing tolerance and, indeed, support for a smarter approach that could change, and even save, countless lives.

Now, the question is how the federal government will respond to these new state laws, since they directly conflict with existing federal restrictions on drugs. Recreational use might be legal in the eyes of Colorado and Washington, but Uncle Sam can still put the boot down.

President Obama has a choice. He could direct the Department of Justice (DOJ) to crack down and prevent the two states from moving forward. Or he could finally, fully embrace sensible drug laws.

There are reasons to be encouraged. During the 2008 campaign, Obama pledged to leave state medical marijuana laws alone. He seemed to sympathize with the African American and Latino communities, disproportionate casualties of the drug war. Surely, Obama knew that one chance run-in between his youthful “choom gang” and the police years ago would have deprived him of the office he holds today.

In October 2009, the DOJ declared that the federal government would not prosecute individuals, including distributors and cultivators, found in possession of marijuana, as long as they were complying with state medical marijuana laws.

The following year, President Obama signed the Fair Sentencing Act, which dropped the five-year mandatory minimum sentencing for simple possession of crack cocaine. The law also reduced the unjust disparity in federal sentencing for crack and powder cocaine.

But in October 2011, the DOJ began large-scale raids on medical marijuana cultivators and distributors, state law be damned. Federal authorities have since raided and shut down 600 dispensaries in California alone. A fine use of law enforcement resources in these austere times.

Enough is enough. The president should instruct the DOJ to de-prioritize marijuana-related cases in states that allow for medical marijuana, and to allow Colorado and Washington to move ahead with implementation of their new laws. He should ensure that federal appointees dealing with the issue, including U.S. Attorneys, are fair-minded.

And he should take the fight to Congress, where members of both parties might be able to find common ground. Obama can lead across party lines by seeking out libertarian members of the GOP to join him in crafting better drug policies. In fact, in May, Democratic Reps. Sam Farr (Calif.) and Maurice Hinchey (N.Y.) joined with Republican Dana Rohrabacher (Calif.) on a bill that would have cut federal funding for the Justice Department’s marijuana busts. And Senator Rand Paul recently indicated he might work with Democrat Pat Leahy to eliminate mandatory minimum sentences for marijuana possession.

Meanwhile, if left free of federal intrusion, Colorado and Washington might become a model for legalizing and taxing marijuana. If successful, the experiment could yield millions in tax revenues and drastically decrease incarceration rates, while giving members of Congress more incentive to change federal law. It could even help improve U.S. relations with Latin America, and help demilitarize our hemispheric policies with our closest neighbors, particularly Mexico.

If Congress fails and, four years from now, a new president instructs the DOJ to crack down again, any such reforms would be at risk. But if Colorado and Washington show positive results, the public, which already believes the drug war has failed, might support wider implementation, and perhaps force a federal solution.

To be sure, Colorado and Washington are not the final battlefields of the war on drugs. Marijuana is not the sole drug behind our astounding incarceration rate for nonviolent drug-related crimes. We’re a long way from a just system that addresses drug use with treatment rather than punishment. Still, we might be one step closer to ending our failed attempt at marijuana prohibition, much as, in 1933, public opinion finally brought an end to alcohol prohibition.

In the first proclamation of Thanksgiving, President Lincoln acknowledged the many gifts bestowed by a god who, “while dealing with us in anger for our sins, hath nevertheless remembered mercy.” This holiday, as President Obama pardons the traditional turkey, let’s hope he also considers the millions of Americans trapped in a cruel, senseless system. May he heed Lincoln’s words and offer them forgiveness and, above all, hope.