WASHINGTON — One day he is committing a string of verbal miscues, saying there is no “silver bullet” but that he is “shooting for Tuesday” in completing an ambitious gun control proposal. The next day, he’s the power behind the presidency.

Vice President Joe Biden — who is the other person taking the oath of office this weekend — has over the last four years refined one of the best shticks in politics, in which one of his biggest problems (his mouth) has become one of his greatest assets (his ability to connect).