President Obama visited Mexico on Thursday for the first time since taking office. Appearing with Mexican President Felipe Calderon, Obama vowed US cooperation in cracking down on drug cartels along the US-Mexico border.

President Obama: “At a time when the Mexican government has so courageously taken on the drug cartels that have plagued both sides of the borders, it is absolutely critical that the United States joins as a full partner in dealing with this issue, both through initiatives like the Merida Initiative but also on our side of the border in dealing with the flow of guns and cash south.”

Despite the talk of cooperation, Obama rejected Calderon’s key demand to push for reimposing the congressional assault weapons ban. Calderon says violence has significantly increased since the ban expired in 2004.