Aside from the Bible, one of the best books you (or any other Christian) will ever read in answer to this op's question is Francis Schaeffer's
trilogy. Every Christian should read it (along with J. I. Packer's "
Knowing God." Schaeffer surveys philosophy, history, art, and music to chronicle the evolution from the early days of western civilization to postmodernity. There was a time when the Judeo-Christian worldview was so predominant it was the standard and filter for everyone's thinking - even the non-Christian. Simply put, America was Christian simply because there was no other competing worldview..... and people acted accordingly.
So, yes, America was a much more Christian nation "
back then," no matter when "
back then" was.
It is common for those on the liberal end of theology and politics to claim the founding fathers were not all Christians and did not establish the nation based on Christianity but that is demonstrably false. Nearly all of the members of the Continental Congress were either clergy or held positions as elders or vestry members in their congregations. Even purported atheists thought in terms of the Judeo-Christian worldview and their understanding of the Bible. Anyone who actually opens up Thomas Paine's "
Common Sense" or "
Rights of Man" is near-instantly confronted with Paine writing about God and quoting from the Bible. There are
scores of references to God and scripture in his writing. If he was an atheist then he was not a very good one and he nevertheless held a Judeo-Christian worldview originating straight from the Bible. Lstly, for now, every single colony but one (Rhode Island) had laws prohibiting atheists from holding political office (sadly, most of them required a sectarian affiliation).
Think about what would happen today if the states prohibited atheists from holding office.
Yes, America is less Christian.
BUT the answer to that question also depends on what you mean by Less Christian," because Americans and Christianity has always had a problem with hypocrisy (and legalism). The way a person
thinks and the way a person
acts are different. To say, "
It's not supposed to be that way," is to assert a standard that comes directly out of the Bible.
I suspect many people are not going to like my answer, so I encourage you to check it out for yourself. I'm going to blow through some history here so if you want more detail just ask.
Remember America came into its own at the end of the 18th century. The French Revolution followed the American Revolution but the two were fought for entirely different values. Whereas America was originally populated by religious people seeking religious liberty and less governmental control, the French Revolution was fought to discard religion and the monarchy. The fight for "Reason," as the French purportedly lauded was more despotically violent and prejudiced than anything any monarchy had ever manifested. The French Revolution was also classist at its core because of abuses by the monarchy. America has never had a monarchy. Soon after the French Revolution, Napolean come into power and He at his coronation he infamously took the crown out of the Pope's hand and crowned himself. Symbolically that was transitional because it meant man could crown himself. It is one of the most humanist acts in human history. Then came the Napoleonic wars and in the middle of the 1800s the American Civil War. At the time those events were considered end times events. Really. A large swath of Christendom perceived these events as apocalyptic. I'll write more on that below but for now I'll stick with secular events. In the mid-to late 1800s Charles Darwin wrote his books on evolution. Hegel and Schopenhauer were the prominent philosophers but as the 1800s progressed two philosophers, Soren Kierkegaard and then Frederich Nietzsche, became popular and they provide a huge departure in worldviews. Kierkegaard was a Christian and he developed Existentialism whereas Nietzsche was humanist and developed nihilism. Politically, Karl Marx was replacing John Locke and Immanuel Kant, and writing his books and by the end of the century had written his first books on psychosexual theory.
ALL of these events and persons had profound effect on the 20th century, especially in Christian thought, doctrine, and practice.
In the Christian arena huge changes began with Jonathan Edwards, George Whitefield, John Wesley and the Moravians in the late 1700s. Christianity was moving away from creedalism (learning Christianity through the creeds) to experientialism. Three conditions facilitated this: 1) the printing press made it possible for many ordinary people to own Bibles so they could read it on their own and not depend on clergy, 2) America was unsettled and the institutional Church was not established as pervasively as it was in Europe, and the practice of tent revivals lent itself to experientialism. Wesley had been an Anglican minister, but he wasn't a Christian when he embarked on his first mission trip. He was persuaded to Christ through the preaching of Moravians he met on the boat trip home. Eventually converting to Christ he returned to lead a successful revival in the southern part of America while Whitefield was doing his thing in New England. Wesley did not intend to start up a whole new denomination but his "methodism" became common practice with other traveling preachers. You could know you were saved when you had a conversion experience. That alone was a huge changing point in Christian thought, doctrine, and practice. Experientialism began to replace creedalism. This became a problem because as America expanded west there was no oversight for the traveling preachers. That meant there was no uniformity, and no accountability.
The 1800s saw the beginning of what is now known as the "
Restoration Movement." The basic beliefs of the restoration movement were 1) the Church is corrupt, 2) because the Church is corrupt the Church is in need of restoration, 3) our sect has the correct New Testament understanding so come join us because 3) the world is going to end any day now and Jesus is coming to judge everyone so get right with God right NOW. All these movements were apocalyptic and held the traditional orthodox, mainstream Church corrupt. During this time there was a HUGE explosion of new sects and denominations. It made the Reformation look like a trial run. Among these new sects were the Campbellites, the Millerites, the Church of Christ, the Brethren, the Darbyites (Extreme Brethren), the Seventh Day Adventists, the Jehovah's Witnesses, the Latter Day Saints. Many of them were outright cults but many of the managed to stay with an acceptable range of orthodoxy even though there was vigorous debate from those on the creedal end of things. The 1800s also saw the increase in what we now call Liberal Theology. Central Eurean theologians began to question the literalness and historicity of the Bible. The questioned the factualness of the Bibe. This wasn't new. Thomas Jefferson had, a century earlier, cut out all the miracles from his Bible and published his version. Prior to that humanists like Erasmus departed from traditional views. By the end of the 1800s theologians like Frederich Schleiermacher and Albert Schweitzer were gaining popularity among the liberal minded. Schweitzer believed Jesus and the apostles were mistaken: they expected Jesus return during the first century and since that did not happen, they must have misunderstood God. Their views eventually gave rise to The Jesus Seminar.
By the turn of the century three conditions furthered these influences. One was the invention of the radio. Restorationists took to the airwaves. Liturgical, institutional congregations did not need to do so because they had a ready-made audience. The Azusa Street Revival caused another huge explosion in sectarian diversity, birthing the Pentecostal movement. Most importantly, though, John Darby's Premillennial Dispensationalism took hold. It was pushed forward by Cyrus Scofield's commentary Bible (it sold hundreds of thousands of copies), and the founding of the first seminary specifically devoted to Dispensationalism by Lewis Sperry Chafer. Originally called Evangelical Theological College, we know it today as Dallas Theological Seminary. Dispensationalism was
literally invented by John Darby. It did not exist prior to the 1800s. Darby also invented his own hermeneutic. His hermeneutic did not exist before the 1800s. The reason this is important is because it was the primary force carrying restorationism into the 20th century. All of those restorationist sects predicted Jesus would return in the 1800s and that did not happen. I cannot communicate how huge this was. Thay all had to either change their doctrines or "recalculate" their predictions. Most, but not all, of them were also rapturist. They predicted the world was going to hell in a handbasket, the Church was corrupt so it would become increasingly impotent, God would come for the pure Church to rescue them from the soon pending apocalypse.
None of it ever happened.
So....
Many Americans watched as liberalism increased and the teachings of the evangelicals proved false. Church life became less intellectual and more sensationalistic. Conservative leaders in the more historical, orthodox, mainline denominations tried to confront all these influences but had only modest success. Dispensationalism is now very popular and many Christians incorrectly think Dispensationalism is the only view the Church has ever held. I forgot to mention one other point: Many, not all, of the restorationists were also isolationist. Darby, for example, taught Christians needed to separate entirely from the world. They should not hold political office or work in the government. This removal of the Church from leadership and the marketplace of ideas proved fatal. By the late 60s "free love," drugs, and questioning authority was a new norm. It reached its pinnacle (or one of them, at least) with Roe v Wade. That court decision shocked Conservative Christianity and prompted Schaeffer (and others) to examine how the Church got so lazy and uninvolved that this would happen.
In my lifetime Premillennial Dispensationalism has taken hold as the norm through mass media. I read Hal Lindsay's books in the 70s before I was a Christian. Chuck Smith, the founder of Calvary Chapel and many, many others were writing books teaching Christians to prepare for the rapture and Christ's return in 1988. Seriously. They specified a year. Later, others like Harold Camping and Edgar Whisenant, and many others continued preaching rapturism not a single prediction any Dispensationalist has made in the last 180 years has ever come true.
Americans inside and outside the Church hear this and wonder why it is Christianity is wrong and why no one in the Church does anything to stop these men (and women). It bears a bad witness.
my apologies for the length