Religion Indispensable to U.S. Government - an Outsider's Opinion

Alexis de Tocqueville studied American in depth in the 1800's. According to Wikipedia, he "was a French political thinker and historian best known for his Democracy in America..." And, "Democracy in America (1835), his major work, published after his travels in the United States, is today considered an early work of sociology and political science."

One of the statements from Democracy in America is, "Thus whilst the law permits the Americans to do what theyplease, religion prevents them from conceiving, and forbids them to commit what is rash or unjust." Religion in America takes no direct part in the government of society, but [religion] must nevertheless be regarded as the foremost of the political institutions of that country;" [boldface added for emphasis]

The Library of Congress recognizes his work as shown below:

Religion Indispensable to Republican Government
Tocqueville's impression of American attitudes toward the relation of government and religion was formed on his tour of the United States in the early 1830s during the high tide of evangelicalism:

'I do not know whether all Americans have a sincere faith in their religion; for who can read the human heart? but I am certain that they hold it to be indispensable to the maintenance of republican institutions. This opinion is not peculiar to a class of citizens or to a party, but it belongs to the whole nation and to every rank of society.'