The existence of the Constitution is why it is a Secular based nation where it is a nation based on laws made by a lot of Deists who wanted to keep Religion separate from government avoiding the Theocratic based governments Europe were largely composed of at the time.
National Humanities Center
Deism and the Founding of the United States
Darren Staloff
Professor of History at the City College of New York and
the Graduate Center of the City University of New York
Excerpt:
In recent decades, the role of deism in the American founding has become highly charged. Evangelical and/or “traditional” Protestants have claimed that Christianity was central to the early history of the United States and that the nation was founded on Judeo-Christian principles. They point to the use of prayer in Congress, national days of prayer and thanksgiving and the invocation of God as the source of our “unalienable rights” in the Declaration of Independence. Secularists respond that large fractions of the principal founding fathers were not Christians at all but deists and the American founding was established on secular foundations. Their principal evidence is the strict separation of church and state they find embedded in the first amendment. They further cite the utter absence of biblical references in our principal founding documents and note that the God of the Declaration of Independence is not described in a scriptural idiom as “God the Father” but instead in deistic terms as a “Creator” and “supreme judge of the world.” Although both sides have some evidence, neither is persuasive. Ultimately, the role of deism in the American founding is just too complex to force into such simplistic formulas.
Deism
Deism or “the religion of nature” was a form of rational theology that emerged among “freethinking” Europeans in the 17th and 18th centuries. Deists insisted that religious truth should be subject to the authority of human reason rather than divine revelation. Consequently, they denied that the Bible was the revealed word of God and rejected scripture as a source of religious doctrine.
LINK
and,
Cornell Law
Congress shall make no law respecting an establishment of religion,
or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.
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The First Amendment guarantees freedoms concerning religion, expression, assembly, and the right to petition. It forbids Congress from both
promoting one religion over others and also
restricting an individual’s religious practices. It guarantees
freedom of expression by prohibiting Congress from restricting the press or the rights of individuals to speak freely. It also guarantees the right of citizens to
assemble peaceably and to petition their government.
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That statement is clearly Secular as
state religion was prohibited.
The Founding Fathers wanted to keep religion out of the government while affirming all the people have the right to be religious.
You can't ignore the history behind it.