Democrats are blushing. And not because Anthony Weiner is back on Twitter, direct-messaging pretty young girls. Vice President Joe Biden has long held the title of “Liberal Loose Cannon.” But Biden is such a grand hugger and hand-shaker that Democrats still let him work the crowds, crossing their fingers that he won’t say something like: “In Delaware, the largest growth in population is Indian Americans, moving from India; you cannot go to a 7-Eleven or a Dunkin’ Donuts unless you have a slight Indian accent… and I’m not joking!” Slips-of-tongue are easily forgiven (we all make them). But, lately, the...