The same top Bush administration neoconservatives who leap-frogged Washington’s foreign policy establishment to topple Saddam Hussein nearly pulled off a similar coup in U.S.-China relations—creating the potential of a nuclear war over Taiwan, a top aide to former Secretary of State Colin Powell says. Lawrence B. Wilkerson, the U.S. Army colonel who was Powell’s chief of staff through two administrations, said in little-noted remarks early last month that “neocons” in the top rungs of the administration quietly encouraged Taiwanese politicians to move toward a declaration of independence from mainland China — an act that the communist regime has repeatedly warned...