For football fans eager to see a new team in the Super Bowl, the conference championship games on Sunday that sent the Kansas City Chiefs and San Francisco 49ers back to the main event of American sports culture were sorely disappointing.

But one thing is new: Taylor Swift. And she is driving the movement behind Donald Trump bonkers.The fulminations surrounding the world’s biggest pop icon — and girlfriend of Travis Kelce, the Chiefs’ star tight end — reached the stratosphere after Kansas City made it to the Super Bowl for the fourth time in five years, and the first time since Ms. Swift joined the team’s entourage.

The conspiracy theories coming out of the Make America Great Again contingent were already legion: that Ms. Swift is a secret agent of the Pentagon;“I wonder who’s going to win the Super Bowl next month,” Vivek Ramaswamy, the conspiratorial presidential candidate, turned Trump surrogate, pondered on social media on Monday. “And I wonder if there’s a major presidential endorsement coming from an artificially culturally propped-up couple this fall.”

The pro-Trump broadcaster Mike Crispi led off on Sunday by claiming that the National Football League is “rigged” in order to spread “Democrat propaganda”: “Calling it now: KC wins, goes to Super Bowl, Swift comes out at the halftime show and ‘endorses’ Joe Biden with Kelce at midfield.”