Graham Stack, a freelance journalist hired by Fusion GPS, says the opposition research firm was “almost completely wrong” about former Trump campaign chairman Paul Manafort. Stack says Fusion GPS provided most of the research cited by the media that suggested Manafort was a Kremlin stooge. Stack says he “shares the blame” for pushing the research, which he now says is part of a false narrative. A former contractor for Fusion GPS claims the opposition research firm got its investigation of former Trump campaign chairman Paul Manafort “almost completely wrong.” Graham Stack, who was hired by Fusion GPS in July 2016,...