Check out this month's Foreign Affairs for Charles Kupchan's takedown of the League of Democracies idea. Kupchan's piece is one of the most comprehensive cases made against the League yet, demonstrating how it would have serious logistical issues, be completely unworkable, and beyond that it would actively exacerbate tensions. Oh, and no other democracies besides the US think it's a good idea or want to join. Well done, Mr. Kupchan. Couldn't have said it better myself.
I hope Barack Obama reads this piece.