Chris LaCivita, a top adviser to President Donald Trump, insists that Elon Musk will not cut Social Security in his pursuit to limit government because Musk is “not president” and therefore “doesn’t get to make those decisions.

The involvement of Antonio Gracias, an investor who has known Elon Musk for two decades, suggests that Mr. Musk has made overhauling the Social Security Administration a priority.

The two maintain that they won’t attack the program, but their repeated claims of rampant fraud serve a strategic purpose.