President Joe Biden was flanked by two Marines and bathed in red light against a brick wall as he delivered a prime time address in which he told Americans that those he called “MAGA Republicans” were a threat to the United States and to American democracy. Biden delivered the speech at Independence Hall in Philadelphia, the birthplace of both the Declaration of Independence and the Constitution. But the style of his address — carried on every news network — oddly recalled that of leaders in military juntas.