Are we similarly to disregard "All men are created equal" as well? That seems silly.
In case you've forgotten your history (really shouldn't sleep through class, chum1) the only place the separation between church and state exists is in two letters, written back and forth, between Thomas Jefferson and the Danbury Baptists. The Danbury Baptists, in a letter to President Jefferson dated October 7, 1801, affirmed that "Our Sentiments are uniformly on the side of Religious Liberty — That Religion is at all times and places a matter between God and individuals — That no man ought to suffer in name, person, or effects on account of his religious Opinions - That the legitimate Power of civil government extends no further than to punish the man who works ill to his neighbor...". President Jefferson, in a response dated January 1, 1802, wrote, "I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should 'make no law respecting an establishment of religion, or prohibiting the free exercise thereof,' thus building a wall of separation between Church & State."
That's it. It doesn't appear anywhere else. The essense of the letters is that the government should not establish a government run religion. By the SCOTUS having the rulings that they have done, in effect the government has established the religion of Secular Humanism.