Ken Thomas at No Left Turns discusses the Elena Kagan’s dismissal of the Declaration of Independence as the foundation for constitutional liberties.
From Preserving Democracy, p. 230:
Religion in America serves three very important functions in regards to democracy. The first is that it provided the intellectual foundation for the country, as stated by the Declaration of Independence. Remove the Declaration’s claim that our rights come from our creator and you are left with the question of where do they come from?