Colombia's Constitutional Court Friday approved the government's proposal to decriminalize the possession of small amounts of cocaine and marijuana for personal use. Anyone caught with less than 20 grams of marijuana or one gram of cocaine for personal use may receive physical or psychological treatment depending on their state of consumption, but may not be prosecuted or detained, the court ruled.

Colombia's move is part of a growing trend in Latin America. After decades of being brutalized by the U.S. government's failed prohibitionist drug policies, Latin American leaders are saying "enough is enough."

Last week, the government of Uruguay announced that it will submit a proposal to legalize marijuana under government-controlled regulation and sale, making it the first country in the world where the state would sell marijuana directly to its citizens. The proposal was drafted by Uruguayan President Jos Mujica and his staff and requires parliamentary approval before being enacted.

Friday's judicial ruling in Colombia represents yet another important step in the growing political and judicial movement in Latin America and Europe to stop treating people who consume drugs as criminals worthy of incarceration. It is consistent with prior rulings by Colombian courts before former president lvaro Uribe sought to undermine them, and also with rulings by the Supreme Court of Argentina in 2009 and other courts in the region. The Colombian Constitutional Court's decision is obviously most important in Colombia, where it represents both a powerful repudiation of former president Uribe's push to criminalize people who use drugs and a victory for President Juan Manuel Santos' call for a new direction in drug policy.

Most decriminalization initiatives in Latin America, however, are being proposed and enacted not by courts but by presidents and national legislatures. In addition to President Santos, Guatemala's new president, Otto Prez Molina, is an advocate of decriminalization as are - in various ways and to different degrees - the presidents of Costa Rica, Uruguay, Ecuador and Argentina. Some Latin American countries, it should be pointed out, never criminalized drug possession in the first place. This trend follows in the footsteps of European reforms since the 1990s. Portugal, which decriminalized drug possession in 2001, stands out as a model.

Decriminalizing drug possession appears to have little impact on levels of illicit drug use. Its principal impacts are reducing arrests of drug users, especially those who are young and/or members of minority groups; reducing opportunities for low level police corruption; allowing police to focus on more serious crimes; reducing criminal justice system costs; and better enabling individuals, families, communities and local governments to deal with addiction as a health rather than criminal issue.

The United States clearly lags far behind Europe and Latin America in ending the criminalization of drug possession. Momentum for reform is growing with respect to decriminalization of marijuana possession, with Massachusetts reducing penalties in 2008, California in 2010, Connecticut in 2011 and Rhode Island earlier this year. All states, however, treat possession of other illegal drugs as a crime. Thirteen states, the District of Columbia, and the federal government currently treat possession of drugs for personal use as a misdemeanor, with penalties of up to a year in jail. The remaining thirty-seven states treat possession of cocaine, heroin and other drugs as a felony, with penalties than can include many years in prison.

While decriminalization certainly represents an important step in the right direction, it does not address many of the greater harms of prohibition, including high levels of crime, corruption and violence, empowerment of criminal organizations, massive black markets and the harmful health consequences of drugs produced in the absence of regulatory oversight. Decriminalization of drug possession is a necessary but not sufficient step toward a more comprehensive reform of the global drug prohibition regime.

Ethan Nadelmann is the executive director of the Drug Policy Alliance (www.drugpolicy.org)