Reservations had been mounting about the risks Tucker Carlson presented for the network ahead of his ouster. Photo: Getty ImagesTucker Carlson said he is launching a new show on Twitter, after he was ousted from Fox News in April. “Starting soon, we’ll be bringing a new version of the show we’ve been doing for the last six-and-a-half years to Twitter,” Mr. Carlson said in a video posted to the social-media platform Tuesday afternoon.

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