President Obama apparently feels that he's had enough summitry for a while - all those meetings, all those poobahs, all that protocol. Well, yes, but that's the essence of multilateral diplomacy.
So does this mean the United States will revert to its evil, unilateral ways?
I doubt it: Obama likes to delegate. He delegates budgetary, energy, and health policy to the Congress, and seems to like to delegate foreign policy to the United Nations and other bodies such as the Organization of American States (you know, the guys who just trashed Honduras).
Letting the other guys take the lead is also attractive when you've just attended a whole string of summits where you've actually gotten very little of what you wanted.