Francis Fukuyama blames populism: 

Americans with their democratic roots generally do not trust elite bureaucrats to the extent that the French, Germans, British, or Japanese have in years past. This distrust leads to micromanagement by Congress through proliferating rules and complex, self-contradictory legislative mandates which make poor quality governance a self-fulfilling prophecy. The US is thus caught in a low-level equilibrium trap, in which a hobbled bureaucracy validates everyone’s view that the government can’t do anything competently. The origins of this, as Martin Shefter pointed out many years ago, is due to the fact that democracy preceded bureaucratic consolidation in contrast to European democracies that arose out of aristocratic regimes.