WASHINGTON - More and more, top government diplomats are straying from official Bush foreign policy as the administration wanes, leaving Secretary of State Condoleezza Rice struggling to keep them in check. Twice just this week, Rice and her aides had to rebuke, disavow or otherwise try to explain away public words or actions by three top officials on delicate affairs ranging from North Korea and Iran to the violence in Kenya. The trouble began on Jan. 17, when Jay Lefkowitz, the special U.S. envoy for human rights in North Korea, delivered a speech at the conservative American Enterprise Institute think-tank...