Which two U.S. presidents were Quakers?

Two U.S. presidents, both Republicans, were Quakers (lifelong members of the Religious Society of Friends). They were Herbert Hoover (1929 – 1933) and Richard Nixon (1969 – 1974).

As Quakers customarily do not swear oaths of office, it was expected that Herbert Hoover would affirm the oath of office, and most historical sources state that he did so. However, it is interesting to note that a Washington Post article dated February 27, 1929, stated that Hoover had planned to swear, rather than affirm, the oath.

Concerning President Nixon, he swore the oath of office at both of his inaugurations. He also engaged in military service, contrary to the Quaker doctrine of pacifism.