Former New Jersey Gov. Chris Christie helped build Donald Trump up in the 2016 presidential primary and now he’s trying to tear him down before the 2024 election. He says it’s time for the Republican Party to move on from the boisterous former president and his stolen election claims. The blunt ex-prosecutor and governor has been test-driving his anti-Trump message as part of a public relations blitz around the release of his new book “Republican Rescue,” separating himself from the lion’s share of Republicans who still hail Mr. Trump as their unquestioned leader. But Mr. Christie is trying to pull...