As we look toward Christmas, we can expect some arguments about nativity scenes in government locations. Christmas, after all is said and done, is when Christians of all denominations acknowledge the human birth of Jesus Christ. Christ, as they see it, was fully human, but miraculously also fully God.
Christmas is not a secular holiday, even though a great number of people celebrate it as such. A day off of work, a chance to share time with families, and a sense that we should care more about those around are not important exclusively to those with faith, of course. But, 'Christ'mas is not the same as, say (hypothetically) "Good Will Toward Men" Day.
The question is: to what degree should government organizations, from the White House to the public library, tip their hat toward Christmas?
If the answer is "They should do nothing," then there should be work that day. Floating holidays aside, which cater to all beliefs or nonbeliefs, it cannot be a mandated holiday.
No Christmas parties. No gifts. No Christmas trees. Say what you like about the secular history of a Christmas tree, it is now only a Christmas tree. Nothing else. Put one up, and that's what it is.
If the answer is yes, then, this opens the door to every other religious holiday, including Muslim, Jewish, Wiccan, Hindu, and whatever other religions have at least one government employee present.
In each situation, the matter has absolutes, and progressions. To have 'X', in each case, there is a correlating 'Y'.