Argentina's Supreme Court on Tuesday decriminalized the possession of small amounts of marijuana for personal use, tossing out tough provincial drug laws whose penalties it deemed unconstitutional.
The high court ruling protects "the privacy of adults who are responsible for their own conduct," according to a court statement.
It said the constitution protected "the private actions of individuals who in no way offend order or public morality, or harm a third party, who answer to God free from a judge's authority."
The court ruled on a case involving the trial and sentencing of five young people arrested during a sweep in early 2006, when police seized between one and three marijuana cigarettes from each of them.
While the decision could be seen as a victory for Argentinians seeking to overturn laws which funneled many recreational drug users into the penal system, the court said in its statement that the ruling "cannot be considered legal permission to consume indiscriminately."
The verdict comes just four days after Mexico legalized possession of small quantities of drugs such as heroin, marijuana and cocaine, arguing that limited resources are better used in the fight against organized drug crime.
The change means Mexicans can possess up to five grams of marijuana, 500 milligrams of cocaine, two grams of opium or 50 milligrams of heroin without fear of prosecution.