He survived two assassination attempts while President
Twice attempts were made on Truman’s life while he was President, although only the second is well known. In the first attempt in 1947, Zionist terrorists known as the Stern Gang tried to kill the President (as well as British officials including Foreign Secretary Anthony Eden) through the use of letter bombs. These attempts failed when the letter bombs were diverted by first British police, who then alerted the US Secret Service.
At the time US recognition of a Jewish state of Israel was still much in doubt, one of the reasons being Truman’s concern over such Zionist terror activities in Palestine. Truman later led US recognition of Israel.
The second and more well-known, although myth-laden, occurred during the White House renovation project when Truman and his family were living in the Blair House. Puerto Rican Nationalists wanting an independent state for the island targeted the Blair House in an attempt to kill the President on November 1, 1950.
The attack was near suicidal in nature, and the two attackers engaged in a shootout with White House Police and Secret Service Officers. One attacker and one officer were killed and three others wounded including the second attacker, Oscar Collazo, who recovered. He was sentenced to life imprisonment, later commuted to time served in 1979.
Truman had been napping upstairs in Blair House when the attack began and glanced briefly out of the window towards the gunfight which was occurring about thirty feet away. He was immediately hustled aside by Secret Service officers. This led to the apocryphal story that Truman, awakened from his nap, had shouted out the window demanding to know what was going on.
In reality, Truman was visibly shaken by the attempt and the loss of an officer and mulled over both in his diary for some time after. The myth of his belligerence under fire has only grown with the passage of time.