There is much that Obama is doing that is not particularly peaceful. However, I think that the strongest argument for him deserving it is in a post by me still up here on good news about US-Iran relations. His agreement with Iran about their enriched uranium is a serious move towards reducing the threat of nuclear war in the Middle East, including importantly because it reduces the probability of an Israeli strike by Israel on Iran. This outcome, on the very first day of negotiations, reflected some very smart moves by Obama, including his cancellation of the ABM sites in Eastern Europe, which brought the Russians on board. Also, I would say that the timing of his announcement in Pittsburgh about the second reactor in Iran was perfect.
Beyond this, those who are so loudly complaining about the prize, I am waiting to hear from any of them who was more deserving of it this year who has not already gotten it? Should we give it to the leader of Sri Lanka for ending the war by defeating the Tamil Tigers and killing their leader? Any other candidates?