Ever since Taylor Swift appeared last September at a Kansas City football stadium, with a Chiefs jacket artfully shrugged off her shoulders, large swaths of the nation (I know, not you) have quietly or loudly lost their minds.

Here was the fulfilling of the prophecy foretold in “You Belong With Me,” in which Swift was, in fact, on the bleachers, and this time the guy finally realized that he did belong with her.

Here was the merger of two major fandoms. Here was Megyn Kelly giving her two cents on the couple, and Donald Trump giving his, and Howard Stern proclaiming that Travis Kelce should marry Swift, and my old friend, a literal ordained priest, texting me to say, “If 20 years of listening to the ups and downs of Taylor Swift’s love life ends with her marrying a football player, I am going to be so p—ed.”

By last week, relationship analysis had reached the truly upside-down place, with the launching of an outlandish theory on the right that the entire Traylor romance was part of a plot to win the 2024 election for President Biden.

There is clearly something going on here that has touched a nerve.

Now that Taylor has won her 13th and 14th Grammys, and now that the Japanese Embassy has sent out a formal press release assuring that she can make it back from her Tokyo concert in time to watch her boyfriend play in the Super Bowl, maybe we can figure out what it was.

I keep thinking of Joseph Campbell, the renowned professor of folklore whose works brought terminology like “the hero’s journey” and “follow your bliss” to the masses. He died in 1987, but if he was alive, I think he would have a lot to say about what is happening here.

Even those of us who don’t follow any kind of stadium culture — sportsball, concert — can observe that the Swift/Kelce union represents a fairy tale, a love story in the classic genre.

Boy adores girl from afar. He plots a meet-cute, and it works! Campbell taught that, in terms of culture-shaping, mythology has four functions, the highest of which is that it reveals “how to live a human lifetime under any circumstances.”

Traylor is doing this for us: It is giving us the ingredients of a universal love story, played out by the closest thing we have to demigods in the 21st century.