Justices Keep 'Under God' in Pledge (washingtonpost.com): The Court threw out the case not on the merits of its arguments but because the justices concluded that the plaintiff had no legal right to sue on his daughter's behalf.
However, the three justices who did comment "supported some version" of the White House's Humpty Dumpty claim that "under God" does not actually refer to God Himself but to a historical idea of God. The White House is basically saying here that the phrase "under God" means that the U.S. is not one nation currently under God but is instead one nation founded under God a long time ago.
From Wordspy:
Humpty Dumpty language noun. An idiosyncratic or eccentric use of language in which the meaning of particular words is determined by the speaker.