“I wish you had no narco-trafficking, but it’s not really your fault,” Clinton told an audience of students and business leaders at the recent Laureate Summit on Youth and Productivity. “Basically, we did too good of a job of taking the transportation out of the air and water, and so we ran it over land.

“I apologize for that,” Clinton said.

Clinton was referring to U.S. drug enforcement policy that began under his predecessors, Ronald Reagan and George H.W. Bush, who invested heavily in shutting down the Caribbean Sea as the favored trafficking route between the U.S. and South America and Central America. That effort pushed smuggling west, over land in Mexico.

Clinton made his own contribution. Opening Mexico’s border with the U.S. encouraged land-based trafficking, and enforcement efforts that broke up Colombian cartels empowered Mexican drug gangs, who until then had largely been middlemen. With more power came more money. With more money came more violence.