After four decades and billions of dollars in spending, the U.S.-led "War on Drugs" has failed.

Initially, this war's architects aimed to curb drug use at home and stem production abroad. Their strategy has achieved few gains on either end. Today, an increasing number of states and foreign countries are demanding a new approach to drug policy.

Voters in Colorado and Washington, for example, both passed November ballot initiatives that would regulate the sale of marijuana. Mexico recently decriminalized the personal possession of some drugs, and many other Latin American presidents are calling on the United Nations and other international bodies to reexamine prohibitionist drug policy after decades of violence and little progress.

Why this backlash against the current prohibition strategy? Because it failed to reduce the addiction or the violence associated with the drug trade. Treating drug use as a criminal act rather than a health problem has harmed society. It has led to racist enforcement patterns and landed unprecedented numbers of nonviolent drug offenders in prison, costing taxpayers billions of dollars. In Latin America, it has led to displacement, forced migration, increased criminal profit margins, and the loss of hundreds of thousands of lives.

Prohibition isn't cost-effective either. A 1994 study found that domestic enforcement costs four times as much as treatment to reduce the amount of drug users, seven times as much as treatment to reduce the amount of drugs consumed, and 15 times as much as reducing drug-related violence in communities.

Unfortunately, the drug policy debate favors law and order "toughness" over cost-effective, treatment-based methods. Politicians favor stricter laws, but research repeatedly shows that there is little correlation between "tough" laws and decreased drug use or availability. According to a 2012 RAND Corporation study, the number of people incarcerated for drug-law violations grew tenfold between 1980 and 2010, yet drug prices decreased.

These "tougher" laws have resulted in 500,000 drug offenders in prison — a disproportionately Latino and African-American population — soaring expenses, and little investment in public health programs to treat the root problem.

Even in the face of failed strategies, many fear that "legalization" would eliminate all restrictions on drug use. In fact, a reasonable alternative would be to regulate some or all drugs just as we already do with the most commonly abused substances: tobacco and alcohol.

Polling and voting data show growing support for this alternative. A majority of U.S. citizens believe that marijuana should be legal. More Coloradans voted for regulating marijuana than for reelecting Barack Obama — 54.8 percent versus 51 percent.

Washington's voters joined Colorado in passing a measure regulating the sale of marijuana and several other states have passed laws regulating the sale of medical marijuana. Because these measures are in violation of federal prohibition laws, drug policy reform advocates are waiting to see whether the Obama administration will block them.

It's time to end the failed Drug War and explore alternatives more effective than prohibition. Hopefully, someday soon Congress and the White House will heed the message from voters in Colorado and Washington State.