SAN DIEGO — Hope is the political message of the moment, courtesy of President Barack Obama. Tell that to Lincoln High School students Jennifer Astudillo, Sakeenah Shabazz and Alex Velarde, a trio of increasingly polished political activists. Sakeenah, 16, said hope isn't part of her political equation. “Always go in prepared for the worst, not with your hopes up,” she said. What they've displayed instead is persistence, as they've led a group of high school students in persuading the San Diego Unified School District board to shelve campus air-rifle marksmanship programs. The board confirmed the decision Tuesday, although members eased...