Thanks, dear Benjamin, for sharing your experience. I really don't understand what American nationalism mean. Well, persecuted European Christians settled over there, and were able to build a great nation, but do they have national identity? What I hear is he/she are Italo-Americans, Irish-Americans, German-Americans etc. Is there a Christian-American identity? Does the government which trust in God behave like a Christian? When it comes to global affairs, what we see is the contrary; look what is happening to the indigenous Christians of the Middle East and North Africa. Americans are supporting the Islamic movements to eradicate some of the oldest Christian communities in the world.
"American nationalism" is an interesting concept. Patriotic immigrants usually love their new-found freedom (now, historically many were originally persecuted, especially those from non-Protestant backgrounds).
No, there's not really a "Christian-American" identity in the same sense as there is a Italian-American, German-American, or African-American identity. Those who often try to label themselves as such are politically and socially conservative Protestants, and many of them seek a higher public place for Christianity usually by having prayer in school and work, displaying the 10 Commandments on public property, etc. All fairly harmless until you talk with them. Then you learn they want their particular brand of Protestantism to be the reigning religion. After all, look at how many people freaked with John F. Kennedy became president (he was Roman Catholic). Some fringe groups even claimed that the U.S. would be run from the Vatican!
Our government, I would say, is not Christian. I wouldn't even call our nation Christian. I wish we'd take "In God We Trust" off of the money, because the god of America is, in my opinion, not the God of Abraham, Isaac and Jacob. The U.S. is relatively deistic, if I had to put a finger on the "faith" of our nation (the general tenor of the people/government, that is). This is what we see in many Founding Fathers, particularly the writings of some such as Benjamin Franklin (who once wrote a piece comparing Christ and the Buddha as equals) or Thomas Jefferson (who wrote his own version of the New Testament in which he cut out all of the miracles, including the Resurrection of Christ). America, to personify the country, believes that "there's a God out there somewhere, probably, wandering around..." and that's about it. We're vaguely Christian because our founders were vaguely Christian.
Yes, many of the first English settlers to the U.S. were Christians fleeing persecution, but they were radical reformers (such as the Puritans) who were fleeing more traditional reformers (the Anglicans). The radical and individualistic mindset of such radical reformers has been passed down. The U.S. knows nothing of traditional Christianity. Now, Catholicism has taken hold and that somewhat helps, especially in places with large Catholic populations. However, many Catholics were persecuted when they first came to the U.S. (whether they were Italian, Irish, Hungarian, Polish, etc.) usually because they were Catholics. Some of them (such as the Irish) faced as much racism against as many former slaves under the Jim Crow laws of the south during the Reconstruction era after the Civil War.
Catholicism is now an important minority, but it's still a minority. It exists as a counter-culture, albeit one that is recognized and usually ignored and/or accepted by non-Catholics. Orthodox still have not even attained that. Usually, we're not even recognized as our own thing and find ourselves being put with the Catholics.
Yes, the U.S. is backing many Islamic-based groups in the Middle East that persecute Christians, because they want to bring "democracy" to people, even when it's impossible. We care more about instilling "democratic values" than we do Christian ones these days. Lord, have mercy. The U.S. will often also provide support to faith-based organizations that send Protestant missionaries into traditionally Christian lands, such as sending Protestants to settle in Alaska and converts the native peoples there, who had been majority Orthodox for over a century before the U.S. gained it. They will also backed faith-based initiatives in Eastern Europe that will proselytize Christian peoples (Catholic or Orthodox). This was happening in Russia a great deal as well, but I think a lot of that has been curtailed by the Russian government.