From Carson Holloway at the Witherspoon Institute:
Strict separation of church and state would require us to throw out Thanksgiving as a religious holiday proclaimed by the president. Instead, we should embrace Thanksgiving and throw out strict separationism as a misguided interpretation of the Constitution.
America’s long and venerable tradition of presidential proclamations of thanksgiving—which reaches from Barack Obama all the way back to George Washington—is a standing rebuke to the modern Supreme Court’s interpretation of the Establishment Clause of the First Amendment.
The Establishment Clause famously provides that “Congress shall make no law respecting an establishment of religion.” From the founding to the present, Americans of all points of view have agreed that this provision forbids the creation of a state church or an official religion.
For the last sixty-five years, however, the Supreme Court has held that the meaning of the clause goes further, that it in fact requires a “strict separation of church and state.” The Court announced this meaning in 1947 with its decision in Everson v. Board of Education, it began using it in the 1960s to invalidate acts of government designed to support religion, and it has held to it resolutely ever since, despite strong criticism from sources both on the Court and off of it.
According to the theory of strict separation, the government is forbidden not only to set up an official church or religion, but also to do anything in support of religious belief. It may not invoke its authority on behalf of any particular religion, and it may not even act to foster religious belief in general. To use the language of the Court, the Establishment Clause requires that the government be neutral not only among sects, but also between religion and non-religion.