President Barack Obama’s plan to tighten security at the U.S.-Mexico border is about to get under way: On Monday, about 30 of the planned 532 National Guard troops are scheduled to start their mission in the southern Arizona desert. More will deploy every Monday through the end of September. Of all the troops, 224 will be allocated to the California border. And while the troops will carry guns, they won’t have the authority arrest anyone. They will merely be, as Arizona National Guard spokesman Lt. Valentine Castillo puts it, the “extra eyes and ears” for U.S. Customs and Border Protection agents, positioned at “strategic locations” along the border. “Having those resources and deploying them adequately makes us more effective,” said Mario Escalante, a spokesman for the Border Patrol’s Tucson sector.