SAN DIEGO, Calif.—January 6 has become Aaron Babbitt’s hill to die on. Over the three years since Ashli Babbitt was shot and killed outside the House Speaker’s Lobby at the U.S. Capitol, her husband has made it his mission to investigate her death and seek justice. “It’s not really possible to put it into words,” Mr. Babbitt told The Epoch Times in an extended series of interviews. “I wouldn’t wish it on anybody. But like I’ve said before, I mean, we’re all born with a purpose. You never know what that purpose is until it kicks you right between the...