Not every day a sitting President threatens a media outlet for exercising their freedom of the press, but it's not the first time it's happened.
Of course, most Presidents have been constrained by some modicum of understanding that their oath to uphold the Constitution applies to the whole thing.
If the Trump election campaign wants to sue Twitter for libel, they're welcome to try. The President has already tried suing the New York Times for libel for publishing an op-ed he didn't like.
Of course, most Presidents have been constrained by some modicum of understanding that their oath to uphold the Constitution applies to the whole thing.