“We have staked the whole future of our new nation, not upon the power of government; far from it. We have staked the future of all our political constitutions upon the capacity of each of ourselves to govern ourselves according to the moral principles of the Ten Commandments.”
– James Madison

There is a big difference between a Christian Nation and a nation founded on Christian Principles.
And the most striking of those principles is not forcing your religion, even if it is Christianity on anyone.

In other words, it is never Christian or Christ-like to force anything on anyone, even Christianity, no matter the cost or the situation, as dire as it may be.

The same God, who never changes, allowed Adam and Eve to exercise the freedom and liberty to choose to love Him through obedience to His Commandments, or disobey Him. We know the conclusion to this, and even how dire and sorrowful the consequence of sin is, God never forced them. And even now in the Redemption process, Christ calls gently in longsuffering to us all, that we should repent. 2 Peter 3:9

No where in the Holy Word of God you can find an instance of God forcing anything on anyone.

They lie against God when they claim Him in their efforts of war and enforcing morality. Because the Scriptures are clear:

“Now the Lord is that Spirit: and where the Spirit of the Lord is, there is liberty. ”
2 Corinthians 3:17 KJV

Now God prophesied this will happen. And it is:

a lamb.” The lamblike horns indicate youth, innocence, and gentleness, fitly representing the character of the United States when presented to the prophet as “coming up” in 1798. Among the Christian exiles who first fled to America and sought an asylum from royal oppression and priestly intolerance were many who determined to establish a government upon the broad foundation of civil and religious liberty. Their views found place in the Declaration of Independence, which sets forth the great truth that “all men are created equal” and endowed with the inalienable right to “life, liberty, and the pursuit of happiness.” And the Constitution guarantees to the people the right of self-government, providing that representatives elected by the popular vote shall enact and administer the laws. Freedom of religious faith was also granted, every man being permitted to worship God according to the dictates of his conscience. Republicanism and Protestantism became the fundamental principles of the nation. These principles are the secret of its power and prosperity. The oppressed and downtrodden throughout Christendom have turned to this land with interest and hope. Millions have sought its shores, and the United States has risen to a place among the most powerful nations of the earth.
But the beast with lamblike horns “spake as a dragon. And he exerciseth all the power of the first beast before him, and causeth the earth and them which dwell therein to worship the first beast, whose deadly wound was healed; … saying to them that dwell on the earth, that they should make an image to the beast, which had the wound by a sword, and did live.” Revelation 13:11-14.
The lamblike horns and dragon voice of the symbol point to a striking contradiction between the professions and the practice of the nation thus represented. The “speaking” of the nation is the action of its legislative and judicial authorities. By such action it will give the lie to those liberal and peaceful principles which it has put forth as the foundation of its policy. The prediction that it will speak “as a dragon” and exercise “all the power of the first beast” plainly foretells a development of the spirit of intolerance and persecution that was manifested by the nations represented by the dragon and the leopardlike beast. And the statement that the beast with two horns “causeth the earth and them which dwell therein to worship the first beast” indicates that the authority of this nation is to be exercised in enforcing some observance which shall be an act of homage to the papacy.
Such action would be directly contrary to the principles of this government, to the genius of its free institutions, to the direct and solemn avowals of the Declaration of Independence, and to the Constitution. The founders of the nation wisely sought to guard against the employment of secular power on the part of the church, with its inevitable result—intolerance and persecution. The Constitution provides that “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof,” and that “no religious test shall ever be required as a qualification to any office or public trust under the United States.” Only in flagrant violation of these safeguards to the nation’s liberty, can any religious observance be enforced by civil authority. But the inconsistency of such action is no greater than is represented in the symbol. It is the beast with lamblike horns—in profession pure, gentle, and harmless—that speaks as a dragon.” Ellen White ‘Great Controversy’, pages 440.2- 442.2