From: "Unreconstructed Southerner" [Email him]
I believe that the modern war on Christmas was started in the late 1950's by an organization called "Protestants and Other Americans United for Separation of Church and State" , correctly described by the Archbishop of Boston as a "button down collar version of the [anti-Catholic] Ku Klux Klan", and abbreviated as POAU.
For reasons that Sgt. York would have understood, I was attending an evangelical church in Boston in the early '60's. A student minister (a doctoral candidate at Harvard Divinity School) was a local POAU activist, and I became aware of how the POAU was regularly bringing law suits to suppress Nativity displays, etc.(They sued the Post Office over the stamp at the right.) Of course, in the long term it backfired.