Former U.S. Rep. Trey Gowdy, R-S.C., is calling for the release of a document he says could be a “game-changer” in the scandal over Democratic claims that the 2016 Trump campaign colluded with Russia. Top Barack Obama administration officials peddled the claims, including FBI Director James Comey, who leaked memos to the media to prompt a special counsel investigation. Robert Mueller’s probe, however, concluded there was no collusion and declined to refer obstruction of justice charges. On Sunday, Gowdy said in an interview with “Sunday Morning Futures” with Maria Bartiromo that a transcript of a conversation between an FBI informant...