A sometimes wonkish read: http://www.econ.washington.edu/news/millimansl.pdf

But the conclusions:
• Government provided stable background for this achievement, good education for all: both centrally important
• But this ongoing miracle is mainly due to free-market capitalis
• Know that European economies have larger government role and 20-30% lower income level than US
• Is it possible that by imitating European policies on labor markets, welfare, and taxes U.S. has chosen a new, lower GDP trend?
• If so, it may be that the weak recovery we have had so far is all the recovery we will get