The Establishment Clause of the First Amendment to the U.S. Constitution says that
“Congress shall make no law respecting an establishment of religion . . .”
followed immediately by the Free Exercise Clause:
“or prohibiting the free exercise thereof.”
Together these are called the “Religion Clauses” of the First Amendment.
Some people suggest that they are contradictory: the Free Exercise Clause encourages the exercise of “religion” in every possible sense, and at yet the purpose of the Establishment Clause is to keep religion from being practiced to such a degree that politics are influenced.
The Free Exercise Clause does not say that the government should encourage the exercise of religion in every possible sense.
What it says is that Congress must not prohibit it. That’s all.
The Establishment Clause does not say that the government should keep religion from influencing politics.
What it says is that Congress must not make laws concerning official churches, like the Church of England. That’s all.
There is no conflict whatsoever between saying that the national legislature must not prohibit the practice of faith, and saying that it must not make laws concerning official churches.
Conflict arises only when you try to make the clauses mean more than they do.
Budziszewski goes on to argue that the chief reasons advanced for the Religion Clauses were themselves religious:
The Framers didn’t want the practice of faith prohibited, because they thought we have duties to God.
But they didn’t want Congress to get into the official church business, because they thought religious truth is best promoted by religious competition.
The states, and the people thereof, were left to do as they thought best.