5. John Tyler
Tyler assumed office after the death of William Henry Harrison (who some may claim is the most libertarian President because he did not live long enough to do anything). Tyler served nearly a full 4-year term and used his veto power often, using it on the Third Bank on two separate occasions. He also ended the Second Seminole War and did not use federal troops during the Dorr Rebellion. However, he did annex Texas, which would eventually lead to the Mexican-American War.