Ample clues to the sins of Americans exist in Revelation 1 through 8. Then, in Revelation 9: 20 through 21, we read, “The rest of mankind who were not killed by these plagues still did not repent of the work of their hands; they did not stop worshiping demons, and idols of gold, silver, bronze, stone and wood—idols that cannot see or hear or walk. Nor did they repent of their murders, their magic arts, their sexual immorality or their thefts.”
Truly, those who claim that the US is a Christian nation forget the commandment prohibiting coveting thy neighbor’s goods (on the assumption that native American lands are included, or that might fall under coveting their house).
Then there is the whole Christian thing about graven images of Christ on the cross—especially those who are among the Church of Christ sect—and violating the sabbath by keeping businesses open on Sunday (Saturday if you are a Seventh Day Adventist), and bearing false witness (a serious tea-bagger GOPer sin).
Now, on the assumption that they are “born again” and saved by Jesus (the whole craven images/ taking other gods before me thing remains problematic), you might accept that Christians are saved–except that becoming “born again” requires that they follow Jesus’ teachings.
BTW–Jesus was a Jew, and commanded that his followers believe in his Father–but he did so without overruling all the prohibitions against eating “unclean” animals: pigs, shrimp, catfish etc., which are prohibited in Leviticus.
That leaves an opening for salvation only in ignorance, because God forgives those who do not know they sin. But you have to remember that God know all, so most of those who claim to be Christian are probably damned.
So tell us who these people are who claim that the US is a Christian nation. Could it be that they are the minions of the Anti-Christ—the false prophets that the Lord Himself warned us of in Jeremiah 14: 14: “Then the Lord said to me, “The prophets are prophesying lies in my name. I have not sent them or appointed them or spoken to them. They are prophesying to you false visions, divinations, idolatries and the delusions of their own minds.”