Donald Trump has vowed to pardon jailed Jan. 6 rioters as one of his first official acts if he’s re-elected president, and MSNBC’s Joe Scarborough that should be considered an explicit threat of his authoritarian ambitions. The former president declared in a Truth Social post that his first acts for a second term would be closing the border, “drill baby drill,” and freeing supporters he called “hostages” who were prosecuted and convicted for storming the U.S. Capitol to prevent the peaceful transfer of power. “You know, I’ve been wondering, what do [his supporters] think when he says he is goi…