Solution: Secretary of war to Taft, Roosevelt and Truman - NYT Crossword

A history buff might know this character easily — he succeeded Elihu Root, and has appeared in the puzzle numerous times since 1942 (when he was simply clued “A cabinet member”). Henry L. STIMSON did have a long career that included enlisting in World War I and acting as the war secretary during World War II, as well as overseeing the Manhattan Project. After all that, honestly, I should have known the name. I feel quite a bit less guilty about William BARR over there at 30D, who was attorney general for President George H.W. Bush for two years.