It does not take a sophisticated legal realist to recognize the hopelessness of any claim that the status of Christmas as a state or federal holiday violates the Establishment Clause. Justices don’t want to be the greatest grinches of all time.
And, in any event, under current law it is clear the current Christmas holiday is constitutional. It has a secular purpose and context as well as a religious one—most importantly being the anchor of the holiday season that more than any other boosts consumer spending. Evaluating Christmas as a holiday is a bit like evaluating Christmas displays themselves for constitutionality. A secular context, like enough dancing reindeers or increased GNP, can redeem the religious content. It may seem odd to a layman but the more crassly commercial Christmas becomes, the more it becomes legally safe as a holiday.
But instead of thinking what the current Establishment Clause doctrine means for the Christmas holiday, we can turn the question around and ask what the Christmas holiday means for the meaning of the Establishment Clause.