Montana lawmakers were expected to take a big step forward Thursday on a bill to ban TikTok from operating in the state, a move that’s bound to face legal challenges but also serve as a testing ground for the TikTok-free America that many national lawmakers have envisioned. Montana’s proposal, which has backing from the state’s GOP-controlled legislature, is more sweeping than bans in place in nearly half the states and the U.S. federal government that prohibit TikTok on government devices. The House was scheduled to hold a second hearing vote on the legislation on Thursday. If it’s approved, a final...