Did Obama say " the United States' is not a Christian nation"?

What does he really mean if he said that? did not he claim to be a "Christian"? There is a lot of Evidence that we were formed with the basic rules as that of the Christian life, and our founding fathers were inspired by God, righteousness, and the freedom of free will that the Almighty gave us in spite of our turning away from his goodness and grace. Above anything we ARE a christian nation! but we tolerate any and all religions, even the devil worshipers. A nut has climbed up a building to smear feces on a cross, if he did that on a mosque he would now be on the hit list for beheading as they once had Salman Rushdie on.