Zero Hour: After China's massive drill, US patrols disputed South China Sea

The nuclear-powered warship, leading a carrier strike group, was conducting what the U.S. military called routine training in the disputed South China Sea on Tuesday, headed for a port call in the Philippines, a defense treaty ally. The United States is not alone in carrying out naval patrols in the strategic waterway, where Chinese, Japanese and some Southeast Asian navies operate, possibly increasing tensions and risking accidents at sea.