Perfectionism, no less than isolationism or imperialism or power politics, may obstruct the paths to international peace. Let us not forget that the retreat to isolationism a quarter of a century ago was started not by a direct attack against international cooperation but against the alleged imperfections of the peace.
In our disillusionment after the last war we preferred international anarchy to international cooperation with Nations which did not see and think exactly as we did. We gave up the hope of gradually achieving a better peace because we had not the courage to fulfill our responsibilities in an admittedly imperfect world.
We must not let that happen again, or we shall follow the same tragic road again — the road to a third world war.

Franklin Delano Roosevelt (1882–1945) American lawyer, politician, statesman, US President (1933–1945)

Message (1945-01-06) to Congress, Annual Message (State of the Union)
    (Source)

In 1945, Roosevelt delivered the SOTU as a written message to Congress, not as a speech.

See also Voltaire.