Sign seen last week on the side of a Maine barn: “I stand for the flag. I kneel for God.”

While there may be nothing unusual about such sentiments, posting them in letters big enough to be read by passing drivers is a clear public statement. The passer-by may come away thinking the farmer is promoting a link between religious belief and patriotism.

Also last week, the governor of Louisiana signed a state law requiring that the Ten Commandments, God’s directives given to Moses, should be posted in every classroom. This move is meant to promote a basic link between religion and the civil state.

Donald Trump, the once and would-be president, almost immediately endorsed the Louisiana law as worthy of wider adoption.

The First Amendment of the Constitution states there shall be no law respecting an establishment of religion or prohibiting its free exercise. Under the Amendment, the barn sign works, but the Louisiana law probably doesn’t.

Yet many advocates of recognizing the religious foundation of government call for acknowledging that the U.S. is a Christian country, because it was founded by Christians and reflected their beliefs. Perhaps proponents think they can get around the “establishments clause,” because most major religions recognize the Ten Commandments.

Such a theory runs into practical problems. Even more importantly, it faces overwhelming constitutional issues.

The practical question is simple: which Ten Commandments? Multiple versions of them exist, even among Christian denominations, to say nothing of Jewish and other versions. Who would decide the correct version to be posted? Would the choice favor one religion over another or over nonbelievers?

More important is the principle underlying the Constitution that the American government is secular, separate from any religion and neither promoting nor rejecting any religion. This was part of the revolutionary thinking of the new country.

In Great Britain, the monarch was (and still is) the head of the Church of England. Other European countries have had established religions. The French Revolution, occurring immediately after the U.S. Constitution came into effect, created a secular state, designed to end the dominance of the Catholic Church.

Even before the Constitution and its Bill of Rights, the U.S. had ruled against the imposition of religious beliefs. In the Northwest Ordinance of 1787, the Continental Congress decided in the first of the “articles of compact” that no American would “ever be molested on account of his mode of worship or religious sentiments.”

In the core Constitution, which went into effect two years later, the Framers provided that, upon taking public office, a person should show their allegiance by swearing an oath to God or affirming their commitment, if they would not take an oath. It also stated there would be “no religious test” for holding public office.

In 1790, President Washington wrote: “All possess alike liberty of conscience and immunities of citizenship. It is now no more that toleration is spoken of, as if it was the indulgence of one class of people …”

Then came the First Amendment in 1791. It confirmed that there would be no established religion and no government control of a person’s religious beliefs. It intentionally assured diversity.

Thomas Jefferson wrote the Declaration of Independence. It is difficult to think of anybody more a Founding Father. In 1802, he wrote to a Baptist group that the Constitution built a “wall of separation between church and state.”

Many of those who founded the country or drafted the Constitution would not meet the definition of being Christian if that required accepting Jesus into their personal life. They were deists, who believed in a creator of the universe but not in a deity involved in human affairs.

Those arguing the U.S. is a Christian country focus on the supposed religious beliefs of most of the Founding Fathers. They suggest that their beliefs should always determine the essential character of the country. Justice Samuel Alito seeks to recover “godliness,” a virtue that never enjoyed official status.

The Louisiana governor gambles that a conservative Supreme Court will approve his state’s effort to topple Jefferson’s wall. Once again, religious conservatives would use the Court to impose their views on others.

In a narrower sense, this push for a Christian regime creates yet another wedge issue for the Republicans. A wedge issue can attract voters to a party or a candidate solely on that issue alone, giving its politicians a blank check on all else.

Trump has succeeded by adopting this and many other wedge issues originated by others. He now seeks to assume the mantle of a man of faith and is forgiven his trespasses as a reward for his newfound allegiance. His backers say “he keeps his promises,” because he faithfully and persistently pushes each wedge issue button in return for their support.

Gordon L. Weil formerly wrote for the Washington Post and other newspapers, served on the U.S. Senate and EU staffs, headed Maine state agencies and was a Harpswell selectman.