During the 2016 presidential campaign, Donald Trump accused Sen. Ted Cruz of election fraud, described him as “very unstable,” accused his father of aiding in the assassination of John F. Kennedy, and his insulted his wife. For all his embarrassment, Cruz (and the rest of the GOP field) got crushed by Trump in the primary, and then he shamelessly groveled and worked to get the man who called his wife ugly elected to the presidency. That, apparently, is Ted Cruz’s idea of “fun.” Cruz was asked in a Thursday interview whether he was thinking about another run for president and...