False. Carter endorsed Trump over Cruz. That was the entire point. Liberals, Rockefeller Republicans and the MSM in general prefer the furthest left candidate they can convince Republicans to vote for. Nothing new about that x.
Carter doesn't vote in Republican primaries. Plus, look at what you wrote: "Carter endorsed Trump over Cruz." That's different from saying, "Carter endorsed Trump." Without the words "over Cruz" it sounds like Carter was urging people (his own supporters and admirers) to go out and vote for Trump -- which he wasn't doing.
That was the entire point. Liberals, Rockefeller Republicans and the MSM in general prefer the furthest left candidate they can convince Republicans to vote for.
There are different angles here. Maybe a guy over 90 is just giving an opinion, not working political strategy. And when Democrats do give Republicans tips on who to vote for, their main interest might be in getting Republicans to vote for candidates they thing will lose, not in setting an ideological course for their opponents to follow.