There is broad confusion — by design, some say — about the issue of separation of church and state. The issue is regularly and routinely debated during the holiday season as various factions argue whether or not the government can or should allow clearly religious displays on public property.
In many cases, the arguments against religious displays of any kind at Christmas (or any other time of the year) cites that such displays violate the U.S. Constitution definition of “separation of Church and state”.
The problem with such arguments is that the U.S. Constution says no such thing. Read it here.
The first amendment clearly defines the rights of religion, inclusive of the requirement that Congress is prohibited from imposing any religion on the citizens of the United States.
With the passage of a federal bill declaring Christmas a national holiday in 1870 the issue has increasingly become contentious, usually peaking with each holiday season.
For the record, the prohibtion on Congress is the only official mention of religion in the U.S. Constitution. The back and forth of opposing factions and the lawsuits they file reflect the interpretation of individual judges of the U.S. Constitution. While “separation” is frequently the buzzword in the media, it is rarely upheld by a court because “separation” is not in the Constitution.