In the high-stakes arena of American politics, few figures have risen as meteorically—or as controversially—as Charlie Kirk.

Here’s what to know about Project Blue Beam and what Charlie Kirk and others are saying about the decades-old conspiracy theory’s ties to the most popular topic in the U.S. recently.

Former President Donald Trump will continue his battle to win back Georgia through a rally on Wednesday, this time hosted by influential conservative activist Charlie Kirk. Kirk, 31, gained ...