The ebbing stretch of Rio Grande that divides the Texas city of El Paso from the Mexican city of Juarez may soon become one of the world’s most militarized borders. This week, as Texas Governor Rick Perry went to El Paso to announce that has asked Washington for 1,000 more “boots on the ground” to enforce the border, Mexico’s government ordered 5,000 extra soldiers to Juarez. The armies massing on both sides of the border are marching against a common foe — drug cartels — and the coming months will be a crucial test as to whether they can effectively work together to fight it
