I understand the implication of the 1st amendment. Anyone who reads it knows that it literally tells the government not to infringe on anyone's religion and as such treating them equal; thus by interpretation, the showing of a preferential bias in government (say for christianity) as unconstitutional.

The wall of separation that Madison and Jefferson later discussed as being essential to that amendment is however somewhat lost by not having a clearer language. Take some of the later constitutions in Latin America for example...which literally state in the constitution as the government and church being totally separate entities of one another.

Couple to that the long history of people in office preaching their beliefs with little backlash from the press/contemporaries, and no wonder that wall's a little clouded.