The problem is not, as the president implied, the opposition of an implacable few to the manifest general interest.
Rather, it is that Washington is besieged by mutually offsetting lobbies representing almost every conceivable segment of society. Some (e.g., teacher unions) collect under the Democratic Party banner; some (e.g., independent oil operators) tilt Republican; and many (Wall Street, agribusiness, hospitals) have their hooks in both parties.
I discuss the connection between Olson’s theory, national welfare, and lobbying reform in this Stanford Law Review article, Lobbying Rent-Seeking, and the Constitution.