DIED. Lee Atwater, 40, former chairman of the Republican National Committee; of complications from a brain tumor; in Washington. A savvy political strategist who managed George Bush's 1988 presidential campaign, Atwater was often criticized for his "pit bull" style. It was his idea to use Willie Horton, a convicted murderer who raped a woman after failing to return to a Massachusetts prison following a weekend furlough, to derail Democratic candidate Michael Dukakis. An accomplished guitarist and blues singer, Atwater was featured on last year's R.-and-B. album Red Hot & Blue.