John Trumbull, The Declaration of Independence

Were The Founders Christian? Really?
It depends on what you mean by "Christian". Most were members of the popular denominations of the day. 
Let us consider the signers of the Declaration of Independence, the Articles of Confederation, the Constitution, the members of the First Federal Congress, and the non-signing Constitutional Convention delegates as "Founding Fathers".  Allowing for duplications, there were 204 members of this set. The majority were Anglican, then Presbyterian, and Congregationalist. The rest were scattered amongst the Quakers, Dutch Reform, Unitarians, Catholics, Huguenot, Calvinist, and Lutheran. I think few would be considered fundamentalist Christians who believed in the literal truth of the Bible as we now know them.
Tuesday, a Facebook friend who is also a co-worker, a sincere Christian, and a good man, posted the following, which led to an interesting discussion.
"If reincarnation was real, our Founding Fathers would come back as Flag-waving, Bible-thumping, gun-toting Patriots..Oh, Wait..THAT'S what they were originally!"

I had to reply.
"Mark most of the founding fathers were deists. They were educated men of the Enlightenment. They weren't Bible thumping Christians at all. Jefferson created his own version of the New Testament that did not include Jesus' miracles, which he felt were myths. It did include Jesus' philosophy and words. Deists believed a supreme being created a logical universe and rejected miracles. The First Amendment would not have been written by Bible thumping Christians. Jefferson, Franklin, Hamilton, Madison, Adams, Ethan Allen, Thomas Paine and George Washington were more or less Deists. Most were Masons."


This led to someone else linking to a You Tube video featuring a preacher who made a somewhat convincing (but wrong) superficial argument that the founders were indeed Christians. Perhaps they were, but not the kind of Fundamentalist Christians who dominate the political landscape today. I replied again.
"If you need to believe that the founders were bible thumping Christians in order to reinforce your faith, that's fine. But the kind of Christianity that preaches the literal truth of the Bible, an imminent second coming, along with Book of Revelation apocalyptic events and a rapture of the faithful is a mid nineteenth century development that would be alien to Christians that populated the USA at the time of the Revolution. They were thoughtful people of a liberal minded type who abhorred the thought of a state religion and religious tests for office."
Perhaps that last sentence was a bit of a generalization. Then there was the typical back and forth of some supporting my position and some skeptical. Then the starter of the thread said.
"Tom that is Johns opinion, view but provided no references. so what makes it informative?
Agree with the point of abhoring state religion. The state should not be involved with religion"

So I presented some quotes from the founders to support the argument that they were Deists.
"Mark, deism isn't exactly a religion. It is more of a philosophical viewpoint. Therefore it is difficult to create a list of prominent deists. One has to infer from the writings and statements of a person to determine if someone is a deist since there is no formal membership roll of deists. There are organized “deist” groups today but that is a modern development. If one believes that there is a creator of the universe and that the universe then operates under rational laws without the miraculous interventions of said creator then one can be said to be a deist.

Some quotes that may be inferred as deist by famous Americans:

"God helps them that help themselves." -Benjamin Franklin

"I cannot conceive otherwise than that He, the Infinite Father, expects or requires no worship or praise from us, but that He is even infinitely above it." -Benjamin Franklin

"Let it simply be asked, where is the security for property, for reputation, for life, if the sense of religious obligation desert the oaths which are the instruments of investigation in courts of justice? And let us with caution indulge the supposition that morality can be maintained without religion."-George Washington

"The government of the United States of America is not in any sense founded on the Christian Religion."-John Adams

"As I understand the Christian religion, it was, and is, a revelation. But how has it happened that millions of fables, tales, legends, have been blended with both Jewish and Christian revelation that have made them the most bloody religion that ever existed?"-John Adams

"The creation is the Bible of the Deist. He there reads, in the handwriting of the Creator himself, the certainty of His existence and the immutability of His power, and all other Bibles and Testaments are to him forgeries." -Thomas Paine

"Those who invalidate reason, ought seriously to consider, whether they argue against reason, with or without reason; if with reason, then they establish the principle, that they are laboring to dethrone; but if they argue without reason, (which, in order to be consistent with themselves, they must do,) they are out of the reach of rational conviction, nor do they deserve a rational argument." -Ethan Allen"


And I can find hundreds more quotes from the Founders that show them to be Deists or  Christians very different from the kind we see today in the United States. The misconception that the founding fathers were Christian of the modern fundamentalist sort and that they brought some kind of Favor of the Lord on America is a dangerous belief. They were practical merchants. They understood that extreme or religion taken seriously   gets in the way of business. The Constitution is a mercantile document, more accurately described as a contract in which the people, in general, have little standing. This nation was set up as a business enterprise. Look around you.
The Informer, at Against The Grain Press (no longer available), puts this all out there in excruciating detail. Download and listen to his great interviews with Keith Hansen at the Classic Grassy Knoll here while they are still available.
The complete interviews on CD are available here:
http://thinkorbeeaten.com/theknoll/