MATAMOROS, Mexico — Presidential runner-up Andrés Manuel López Obrador's call for civil disobedience reached the border Friday in a string of protests at international bridges in Nuevo Laredo, Reynosa and here. In Matamoros, a group of about 100 blocked a city street that leads to the Veterans International Bridge at Los Tomates and into Brownsville. "We're here because we are sure that López Obrador won," Rommel Delgado, a 23-year-old teacher, said over the horns of miffed truckers and drivers. Civil unrest here and in other parts of the country, most notably Mexico City, is rooted in the historically close results...