Italy’s constitutional court has overturned a controversial law equating cannabis with cocaine and heroin. The decision could see around 10,000 people released from the country’s overburdened jails.

The court ruled the law was “illegitimate,” without elaborating further.

The law, passed by former Prime Minister Silvio Berlusconi in 2006, has been blamed for Italy’s swelling prison population, as sentences for selling, growing or possessing marijuana effectively tripled.

Official data shows that Italian prisons are operating beyond capacity, with 62,000 inmates residing in facilities meant to house a maximum of 48,000.

The prisoners’ rights group Antigone claims that 40 percent of all inmates are currently serving sentences for drug crimes. Following Friday’s verdict, the previous drug law and its far more lenient sentencing regime automatically takes effect.

Opinions on the issue clearly cut down party lines in the country’s centrist coalition government.

Senator Carlo Giovanardi, one of the architects of the tough law, said the ruling was a "devastating choice from a scientific viewpoint and in the message it sends to young people that some drugs are less dangerous than others," Reuters reports.

But Alessia Morani, an MP with the centrist Democratic Party (PD), said “the ruling puts the final word on one of the most absurd laws that parliament has ever passed in recent years," Ansa news agency cites him as saying.

In January 20133, the European Court of Human Rights ruled that Italy's overcrowded prisons violate the basic rights of inmates, fined the government 100,000 euro ($131,000) and ordered it to institute changes within a year’s time.

Meanwhile, while the legalization push is gaining momentum in the US on a state level, marijuana remains listed in the federal Controlled Substances Act at Schedule I, meaning there is no currently accepted medical use and “a high potential for abuse.”

According to the US Drug Enforcement Agency, “Schedule I drugs are the most dangerous drugs of all the drug schedules with potentially severe psychological or physical dependence.”

While heroin is also classified as a Schedule I drug, Cocaine, methamphetamine and OxyContin are listed as Schedule II, meaning they officially have “less abuse potential” than cannabis.

In an open letter published Wednesday, 18 members of Congress called on President Barack Obama to reclassify marijuana.