The Claremont Institute has been located in Southern California since its founding in the late 1970s. From its perch in the foothills of the San Gabriel Mountains, it has become a leading intellectual center of the pro-Trump right.

Without fanfare, however, some of Claremont’s key figures have been leaving California to find ideologically friendlier climes. Ryan P. Williams, the think tank’s president, moved to a suburb in the Dallas-Fort Worth area in early April.

His friend and Claremont colleague Michael Anton — a California native who played a major role in 2016 to convince conservative intellectuals to vote for Mr. Trump — moved to the Dallas area two years ago. The institute’s vice president for operations and administration has moved there, too. Others are following. Mr. Williams opened a small office in another Dallas-Fort Worth suburb in May, and said he expects to shrink Claremont’s California headquarters.

“A lot of us share a sense that Christendom is unraveling,” said Skyler Kressin, 38, who is friendly with the Claremont leaders and shares many of their concerns. He left Southern California in to move to Coeur d’Alene, Idaho, in 2020. “We need to be engaged, we need to be building.”

As Mr. Trump barrels through his third presidential campaign, his supporters buoyed by last week’s debate, many of the young activists and thinkers who have risen under his influence see themselves as part of a project that goes far beyond electoral politics. Rather, it is a movement to reclaim the values of Western civilization as they see it. Their ambitions paint a picture of the country they want should Mr. Trump return to the White House — one driven by their version of Christian values, with larger families and fewer immigrants. They foresee an aesthetic landscape to match, with more classical architecture and a revived conservative art movement and men wearing traditional suits.