WASHINGTON — The United States should do more to curb the trafficking of guns to Mexico that have armed narcotics cartels and fueled violence that threatens border cities, according to a report released Friday. The report by the Woodrow Wilson International Center for Scholars examines a series of policy options on security cooperation, economic integration, migration and border management. But the 72-page study — "The United States and Mexico: Towards a Strategic... (GunPolicy.org)