Is the US a Christian nation ?

It WAS. and still is. Our founders created our country as a Christian nation. It is our tradition.

What is a nation? It's people. Right now, 62% of our citizens are Christian. Therefore Christianity is dominant.

Officially no, in practice very largely, I think. An interesting contrast to the UK, for which the answer would be officially yes, in practice not much.

Strong Christian tradition ,but in practice I'd say no

A neighbour who went to an English public school told me that there was so much 'chapel' that people either became archbishops or atheists.

The Christians would certainly like to think so, but part of the reason the original settlers came here was for religious freedom. And in that spirit, the founding fathers saw fit to make certain there was no official religion of this country.

Not hardly. It, like many other nations in the world, is very pagan. While many Americans claim to be "Christian", few actually follow/obey the Jesus in the Bible (they follow a different jesus).

It's the mask that's regularly worn....

Well, it used to be more so than now.

No, like any other nation it is not.

The vast majority of Americans, like any other country, are unsaved.

Always was. They just need to get together, and expel the agents of Satan from our country.

No.