Philip Alloysius Hart (December 10, 1912 - December 26, 1976) was a Democratic senator from Michigan. He was nicknamed the Conscience of the Senate, which is also the name of a biography of Hart by Michael O'Brien).
He is the person for whom the Hart Senate Building is named. He served for three terms in the Senate, from 1959 until his death. He did not run for reelection to a fourth term in 1976.
Hart died of cancer in 1976, a few days before his term would have expired and he would have retired.