Charlie Kirk, who was shot and killed on Wednesday, pioneered a new model for conservative political advocacy, merging multi-platform media commentary with in-person gatherings and get-out-the-vote drives. Kirk, 31, was a hugely successful political field organizer, TikTok influencer, radio host, nonprofit leader and public speaker all rolled up in one telegenic figure. One minute, Kirk would be on Fox News promoting his friend President Trump’s agenda; the next, he would be on X or Instagram, inviting young people to start conservative groups at their high schools and college campuses. With Turning Point USA, the nonprofit he co-founded in 2012 at...