It's time for Obama -- as the Hillary character said to the Obama character in the latest devastating sendup of Obama on "Saturday Night Live" -- to "man up." He can't throw the "kitchen sink" back at Hillary. Instead, he has to demonstrate his toughness by connecting with traditional Democrats on bread-and-butter issues, and by reacting to his newfound political adversity with aplomb (i.e., no whining about his press coverage becoming less worshipful).
When Hillary and Bill Clinton talk of Obama as Hillary's pick for vice president, they are targeting Obama's toughness. They surely believe that, faced with a Hillary who will go to the convention and spoil his nomination with a nasty floor fight if she has to, Obama will blink. That for the sake of his party and the cause of change, he'll take a unifying deal that puts him in the No. 2 slot.
Obama is trying to knock down the notion, but has yet to burn his ships behind him by ruling out running as VP in any circumstance. Unless he does, doubts will remain about whether he has the stomach for what Hillary will drag him through. Faced with the implacability of Anton Chigurh, after all, the "outmatched" sheriff in "No Country" retreats into retirement.
About this there can be no doubt: When Hillary said at the beginning of her campaign that she's "in it to win it," she meant it.