Thanksgiving has always been one of the high holy days of American civil religion.

Its rituals are surprisingly widespread — pilgrimages home through packed airports; gatherings of family and friends (and attendant tensions that are the stuff of Hollywood rom-coms); the dining room altar on which the turkey is supped, then a long day of drifting in and out of consciousness while hours and hours of football flicker in our darkening dens.

Our Thanksgiving traditions reflect the country’s mix of secularization and religious fervor — what theologian William Cavanaugh calls “migrations of the holy.”

In a secular age, our religious impulses aren’t diminished; they just find new devotions: consumption, the self, the nation. Now, the NFL — in all its popularity and current controversy — sets the script for our Thanksgiving Day litany. It gives us something to worship.

Of course, the typical symbols and traditions of Thanksgiving have their own vague history, which has become both assumed and contested. Those who observe the holiday maintain a baseline spirit of gratitude and pause to “give thanks.” But to whom?

Historically, this gratitude was expressed to God, to the Creator, the Lord of the Harvest, the one in whom we live and move and have our being. Establishing our national observance, Abraham Lincoln commended the nation to “set apart and observe the last Thursday of November next as a Day of Thanksgiving and Prayer to our beneficent Father who dwelleth in the heavens.”

But in a secularized, naturalized world where we are at least officially agnostic about such a being, to whom shall we give thanks? Here’s where the liturgies of football on Thanksgiving provide an alternative.

The pomp and fandom in NFL stadiums across the country display their own rituals — and reveal how our gratitude has shifted. We give thanks to the military, tout our freedoms and celebrate the exceptional blessings of “this great country.” The military serves as the tangible, almost sacramental, embodiment of the nation’s mythology.

Military uniforms are the vestments of these priests of freedom. Watch carefully on Thanksgiving Day: Every opening ceremony and commercial break and NFL halftime show will feature iconic clips of military personnel either at the game or in the field; they will be held up as our way of saying “thank you.” To them we owe our warm homes and overflowing tables and all of the consumer goods we’ll pursue with abandon on Black Friday.

But this year, as protests by players continue, the pigskin spectacle will be particularly fraught. Those who don’t worship in just the right way will be scorned, probably by the president himself.

You know you’ve entered a temple when disagreement is treated as sacrilege. The animosity directed toward NFL players kneeling at the anthem, protesting police brutality and structural racism, is the sort of acrimony we reserve for infidels.

Many professedly “religious” believers will be among those most incensed by resistance to this secular liturgy — a sign that even believers in God are not immune to being captivated by secular rituals, confusing what is holy.

This response to the kneeling controversy tells us something about the state of American civil religion and the way it accommodates — and then deforms — traditional religious communities.

The tropes of “God and country” or “faith and the flag” are almost always instances where country and flag domesticate faith in God. Or, to put this in terms that religious folk should understand: These liturgies of civil religion are covert modes of idolatry. The rank and priority are reversed; our political identities trump all others.

This is how stadiums became temples of nationalism. When the Constitution functions like Scripture, and the pledge serves as our creed, and the flag is revered like the cross, and the national anthem becomes our hymn, and the hand over heart is a sacred expression like the sign of the cross, then a swelling patriotism becomes our religion and dissenters are heretics.

We might not thank God anymore, but that doesn’t mean Thanksgiving isn’t still religious.

James K.A. Smith is professor of philosophy at Calvin College in Grand Rapids, Mich., whose latest book, “Awaiting the King: Reforming Public Theology,” was just published by Baker Academic.