For years, the DEA spent billions of dollars, wasted countless lives, and wreaked havoc on the environment to halt the production of marijuana. But these efforts only seemed to strengthen the cartel’s influence in Mexico, leading to more violence and more problems.

It seems like the American government ignored the obvious solution to curtail the cartel’s power: Legalize pot in the United States.

As the United States gradually loosens marijuana laws, Mexican marijuana farmers (and ultimately Mexican cartels) are losing business to competition north of the border.

Recent legislation has even affected the profits of one the most powerful drug trafficking organizations in the world: the Sinaloa cartel. You may have heard of its most notorious member—the elusive drug kingpin “El Chapo” who was even included on Forbes’ list of billionaires in 2009.

The cartel’s origins are in the state of Sinaloa, the center of Mexico’s marijuana production. But more and more marijuana farmers in the region are closing up shop. It’s simply not worth it to cultivate marijuana since the price per kilogram has dropped from $100 to $30 dollars, in just four years, the LA Times reports.

“People don’t want to abandon their illicit crops, but more and more they are realizing that it is no longer good business,” Juan Guerra, the state’s agriculture secretary, told the LA Times.

Legal pot dispensaries, of course, lead to higher quality marijuana strains—something which Mexico isn’t known for.

As one Reddit user wrote:

Another user, however, doesn’t think Mexican weed is that bad.

And as one user puts it:

Ironically, the United States, the main perpetuator of the war on drugs, is known to produce the best marijuana. Pot’s growing popularity is even reflected in sales:

“From 2013 to 2014, the legal market grew from $1.5 billion to $2.7 billion,” according to the LA Times.

Perhaps legalizing marijuana nationwide will be the final nail in the coffin for the cartel’s marijuana business—and maybe even for the cartel. Marijuana, after all, accounts for around 25 percent of the cartel’s total revenue.