This is a Christian Country! Bullshit!
If what you are saying is the majority of the people in this nation are Christian, then I kind of see your point, but to say we're a Christian nation is completely wrong. We have separation of Church and State, in fact that's the very first of the Bill of rights: Congress shall making no law respecting the establishment of religion...
As far as our president's religion, the ideal president would not let any beliefs affect his decision making, be they Islamic, Christian, Jewish etc...
I tend to agree with Thomas Jefferson, our third president, on the topic of religion:
Millions of innocent men, women and children, since the introduction of Christianity, have been burnt, tortured, fined and imprisoned; yet we have not advanced one inch towards uniformity.
-Thomas Jefferson, Notes on Virginia, 1782
But it does me no injury for my neighbor to say there are twenty gods or no God. It neither picks my pocket nor breaks my leg.
-Thomas Jefferson, Notes on Virginia, 1782
Where the preamble declares, that coercion is a departure from the plan of the holy author of our religion, an amendment was proposed by inserting "Jesus Christ," so that it would read "A departure from the plan of Jesus Christ, the holy author of our religion;" the insertion was rejected by the great majority, in proof that they meant to comprehend, within the mantle of its protection, the Jew and the Gentile, the Christian and Mohammedan, the Hindoo and Infidel of every denomination.
-Thomas Jefferson, Autobiography, in reference to the Virginia Act for Religious Freedom
Christianity neither is, nor ever was a part of the common law.
-Thomas Jefferson, letter to Dr. Thomas Cooper, February 10, 1814
And my Favorite:
ay it be to the world, what I believe it will be, (to some parts sooner, to others later, but finally to all,) the signal of arousing men to burst the chains under which monkish ignorance and superstition had persuaded them to bind themselves, and to assume the blessings and security of self-government. All eyes are opened, or opening, to the rights of man. The general spread of the light of science has already laid open to every view the palpable truth, that the mass of mankind has not been born with saddles on their backs, nor a favored few booted and spurred, ready to ride them legitimately, by the grace of God.
-Thomas Jefferson, letter to Roger C. Weightman, June 24, 1826 (in the last letter he penned)
So if you think that a president has to be a Christian then I would respond by saying, one of our founding fathers and earliest presidents wasn't one.
