Our Founding Fathers based our laws on Common Law !

"The purpose of separation of church and state is to keep forever from these shores the ceaseless strife that has soaked the soil of Europe in blood for centuries."-- James Madison

Laws regarding murder, stealing and harming your fellow man pre-date Christian morality (such as it is) in the form of Common Law in use in Europe for centuries before Christianity reared it’s ugly head therein and Common Law was the basis used by the Founding Fathers in establishing this country.

Allow me to cite the Constitution’s 7th Amendment: "In suits at common law. . . the right of trial by jury shall be preserved; and no fact, tried by a jury, shall be otherwise re-examined in any court of the United States than according to the rules of the common law."

A lot of Christians who want to claim their religion as the basis for American law try to claim that Common Law in Europe was based on the Christian religion. The quote which follows from Thomas Jefferson about Common Law and Christianity is an excerpt of a longer piece Jefferson wrote in a letter to Thomas Cooper on February 10, 1814 which directly rebukes the claim that Christianity has anything to do with Common Law:

“For we know that the common law is that system of law which was introduced by the Saxons on their settlement in England, and altered from time to time by proper legislative authority from that time to the date of Magna Charta, which terminates the period of the common law. . . This settlement took place about the middle of the fifth century. But Christianity was not introduced till the seventh century; the conversion of the first christian king of the Heptarchy having taken place about the year 598, and that of the last about 686. Here then, was a space of two hundred years, during which the common law was in existence, and Christianity no part of it.

”. . . if any one chooses to build a doctrine on any law of that period, supposed to have been lost, it is incumbent on him to prove it to have existed, and what were its contents. These were so far alterations of the common law, and became themselves a part of it. But none of these adopt Christianity as a part of the common law. If, therefore, from the settlement of the Saxons to the introduction of Christianity among them, that system of religion could not be a part of the common law, because they were not yet Christians, and if, having their laws from that period to the close of the common law, we are all able to find among them no such act of adoption, we may safely affirm (though contradicted by all the judges and writers on earth) that Christianity neither is, nor ever was a part of the common law.”

Seems history, and the Founding Fathers, disagree with christianity's claims.