Jake from State Farm's blog: "War On Drugs"

Mexico decriminalized small amounts of marijuana, cocaine and heroin on Friday — a move that prosecutors say makes sense even in the midst of the government's grueling battle against drug traffickers.

Prosecutors said the new law sets clear limits that keep Mexico's corruption-prone police from shaking down casual users and offers addicts free treatment to keep growing domestic drug use in check.

"This is not legalization, this is regulating the issue and giving citizens greater legal certainty," said Bernardo Espino del Castillo of the attorney general's office.

The new law sets out maximum "personal use" amounts for drugs, also including LSD and methamphetamine. People detained with those quantities no longer face criminal prosecution.

Espino del Castillo says, in practice, small users almost never did face charges anyway. Under the previous law, the possession of any amount of drugs was punishable by stiff jail sentences, but there was leeway for addicts caught with smaller amounts.

"We couldn't charge somebody who was in possession of a dose of a drug, there was no way ... because the person would claim they were an addict," he said.

Despite the provisions, police sometimes hauled in suspects and demanded bribes, threatening long jail sentences if people did not pay.

"The bad thing was that it was left up to the discretion of the detective, and it could open the door to corruption or extortion," Espino del Castillo said.

Anyone caught with drug amounts under the new personal-use limit will be encouraged to seek treatment, and for those caught a third time treatment is mandatory.

The maximum amount of marijuana for "personal use" under the new law is 5 grams — the equivalent of about four joints. The limit is a half gram for cocaine, the equivalent of about 4 "lines." For other drugs, the limits are 50 milligrams of heroin, 40 milligrams for methamphetamine and 0.015 milligrams for LSD.

Mexico has emphasized the need to differentiate drug addicts and casual users from the violent traffickers whose turf battles have contributed to the deaths of more than 11,000 people since President Felipe Calderon took office in late 2006.