Illegitimi non carborundum!Unattributed

Wikipedia: The phrase originated during World War II. Lexicographer Eric Partridge attributes it to British army intelligence very early in the war (using the plural dative/ablative illegitimis). The phrase was adopted by US Army general “Vinegar” Joe Stillwell as his motto during the war. It was later further popularized in the US by 1964 presidential candidate Barry Goldwater.

The phrase is also used as the first line of one of the extra cod Latin verses added in 1953 to an unofficial school song at Harvard University: Ten Thousand Men of Harvard. This, the most frequently played Fight song of the Harvard Marching Band, is, to some extent, a parody of more solemn school songs like “Fair Harvard thy sons to your Jubilee throng” etc. The first verse goes:

Illegitimum non carborundum;
Domine salvum fac.
Illegitimum non carborundum;
Domine salvum fac.
Gaudeamus igitur!
Veritas non sequitur?
Illegitimum non carborundum—ipso facto!

The phrase is also used as part of a student painted crest on the bottom floor of Hodge Hall at Princeton Theological Seminary.
A wooden plaque bearing the phrase sits prominently on the desk of U.S. House of Representatives Speaker John Boehner.

Latin Phrases