I have what many might consider an unusual hobby. I do some historical reenacting. I focus on the period from the French and Indian War, through the early 19th Century -- Pre "War of 1812". Originally got into it for the camping and shooting flintlocks, but gradually got interested in the real historical elements of it. I am no historical scholar, but because of this hobby of mine I read some. Over the past decade and a half that I've been living part-time among the Colonials I have come to the conclusion that, despite all modern claims to the contrary, the United States of America should never be considered a "Christian" country.
The Pilgrims were Christian. Their intention was to come here to worship and live as they believe God meant them to live. The colonies that were established later were economic enterprises populated by Christian folk, predominantly WASPs. (No slur intended). Colonies grew and things got complicated. We became prosperous.
The colonials were, for the most part, English subjects.
Then in 1773 things began to get ugly. The colonies were not being treated as they felt they should be treated. And, before long there was a movement afoot to sever ties with England - to rebel.
There were those colonials who did not believe that rebellion was the answer, but patience and longsuffering was the answer. Even in England, citizens recognized the unjust way that the colonies were being treated. Members of Parliament debated giving the colonies seats and full representation. There were even popular protest songs against this unfair treatment of English subjects.
As the relations declined, the cries for just treatment began to drown out the voices of Christian reason. Politics became a wedge to split the "Church" community. You were either patriot rebel or Tory loyalist. And once the line was crossed, and the rebellion had begun, no right-thinking Christian could ever claim that the nation which was to be born would be a Christian nation.
And that is where the seed of Americas decline lies, at it's roots. For, if the root is holy then the fruit is Holy, but if the root is bad, then the fruit is bad.
The colonists rebelled against their King. For the secular citizens and Cultural Christians there is no need of discussion, for they have no part in the Kingdom. But, for those who claim fellowship with The Christ, there are grave implications. They have ignored the admonishments of God to be subject to the powers that be. They rebelled not against an earthly King, but against the Word of God.
All the rationalizations, not withstanding, it was rebellion against God. The so-called "oppressions" and mistreatments used to justify the rebellion in the popular press grew out of the lawlessness of the colonists. (Few if any of the alleged woes would have approached the severity of every-day life, in the time The Christ walked His earth)
It was a bad war for any believer to be associated with -- If were are to believe the Word: "For rulers are not a terror to good works, but to the evil. Wilt thou then not be afraid of the power? do that which is good, and thou shalt have praise of the same:"
Now the rebellion's success has no bearing on the right or wrong of it. For even though God, in His foreknowledge, knew this would happen. And, as with all things, we had choices to make and made them. Many Americans though Tori, were forced to leave their homes and were banished, and many were followers of The Christ whose crime was walking according to Romans 13.
What's causing Americas decline? The same thing that causes all nations to decline, they are Nations of Man.
There is only One Nation Under God, and when it is born, it will last a thousand years.