Complex sentence: William Putnam Bundy (September 24,1917--October 6,2000) was an Assistant Secretary of State during the Lyndon B. Johnson administration who had a key role in planning the Vietnam War.
Split into simpler sentences: William Putnam Bundy (September 24,1917-October 6,2000) was a U.S. Assistant Secretary of State during the Lyndon B. Johnson administration. He had a key role in planning the Vietnam War.