PRETORIA, South Africa - President Bush (news - web sites) suggested Wednesday that any U.S. military help in ending brutal civil unrest in Liberia might consist mostly of advisers and trainers to avoid stretching American forces too thinly around the globe. "We won't overextend our troops, period," Bush said at a joint news conference with South African President Thabo Mbeki, who had pressed him on what role the United States would play in the crisis. African nations want the United States to do more to end the bloodshed in the western Africa nation. But U.S. lawmakers, including some leading Republicans,...