It doesn’t look likely now:
Amid U.S. pressure, Fox backs off drug decriminalization bill
— reported by the Houston Chronicle
Mexican President Vicente Fox refused to sign a drug decriminalization bill today, hours after U.S. officials warned the plan could encourage “drug tourism.”
Fox sent the measure back to Congress for changes, but his office did not mention the U.S. criticism.
[snip]
The new bill would have made the decriminalization automatic, allowed “consumers” as well as addicts to have drugs, and delineated specific allowable quantities, which do not appear in the current law.
Under the law, consumers could have legally possessed up to 25 milligrams of heroin, a half a gram of cocaine and about one-fifth of an ounce of marijuana.