OK, so since they didn't mention God or religion, you're saying they didn't bother because it was so obvious it wasn't necessary?
I have a feeling that no matter what the Federal Constitution said, with the possible exception of "All must worship Satan" you'd be able to spin it into them really meaning to establish the US as a Christian nation even though they didn't actually say it.
It is clear from the statements listed above the states recognized Almighty God and by Madison's own statement in #45, reiterated in the 10th Amendment, they were free to establish state denominations. And they were free not to. It was a choice left to the states. Under the Constitution, the US was never established as a Christian nation, however from the statements above it is clear the separate and sovereign states recognized 'Almighty God' (a clear reference to the Judeo-Christian God) as the source for their rights and derived powers. These were the states whose legislatures would elect Senators and the President. One could easily assume, rightly so, that the men sent to the capitol would be Christian and make their decisions accordingly.
Of course this is a moot point since the Republican party destroyed the intent of the Framers that the states and the national government would be equal and the aspect of federalism