The US government's "drone warfare" kills thousands of innocents.
The US has a history of political assasination like no other country on earth, not just of its own politicians, but covert assasination attempts on the leaders of other nations and political systems....all this before the "Tea Party" was even thought of.

This seems like the action of a deranged young man, the likes of which are to be found in any society.
Considering the nature of US politics and the lack of political understanding in supporters of Both US political Parties, It is a miracle that events like this are more commonplace.

That being said, the folks directly affected by this tragedy deserve all our sympathy and good wishes.