Still smarting from the September 11 terrorist attacks in the U.S. and buoyed by their swift demolition of the Taliban regime in Afghanistan, the Americans are opening a second front in their global war on terrorism. Initially, they'll send more than 650 troops to the southern Philippines to train local forces and join them on patrols against Muslim rebels. The fear is that the U.S. will lack the patience and subtlety needed to end the regional terrorist menace without destabilizing fragile administrations and disturbing religious and ethnic sensitivities.