“Is the United States a Christian nation?”
I have commented before that the word “Christian” makes a poor adjective. It doesn’t tell you much that is useful. I have seen lies, error and heresy on sale in “Christian” bookstores, false believers in “Christian” youth groups, and atheists playing “Christian” rock.
Christianity is just not something you can ascribe to groups, especially groups as large as a nation. One becomes a Christian by trusting Jesus Christ for salvation and recognizing him as Lord. Groups can do all kinds of things an individual can’t, but only individuals can be saved.
So what is really being asked here? Here are a few possibilities: