As the South and North come to a split, the South takes the US Constitution and begins to make amendments to it. The South makes sure to begin with the First Amendment, removing the freedom of religion. The South officially bans all forms of religion within the South and make it so that it is a requirement for everyone living in the South to denounce any form of faith based system and embrace scientific findings and research.
Here you see the North celebrating the separation from the South. The North can finally believe as they please and the Empire State Building reflects the celebration by putting up a cross, representing the dominant religion at the time, Christianity. Though the US may not be as large or as strong as it had intended to be, the two semi-independent countries still work together.
President Lincoln, of the North, officially declares the Civil War over with the Gettysburg Address. He declares that the ‘new nation’ will flourish under the watch of God. He does not fail to include the religious leading the North will rely on. President Lincoln creates a strong religious foundation for the North to build on.