At least that was the claim of a, hold your surprise, Tea Party candidate from Deleware by the name of Glen Urquhart. I had heard this story from several places, and MSNBC.com ran a fact check on this. Not that much of one was needed. Anyway, this guy claimed that it was not Thomas Jefferson who first used the term in a famous letter to the Danbury Baptists, but coined by Adolf Hitler himself.
This is funny on so many levels. First of all, the concept of the Separation of Church and State was well established in the 19th Century, and to think that Hitler coined it himself is downright ignorant. That raises the second question, which is, did Hitler believe in Separation of Church and State? The answer, according to scholars is a pretty resounding no. Given his love of Christianity, I don't think it was seriously in doubt.
Why this sudden fascination with comparing everything in American politics to the Nazis? I think it boils down to good old demagogy that is being employed by Republicans and Tea Partiers alike. Of course, the Tea Party is just a sect within the Republican Party anyway.