Ever since the elitist left lost the mid-term elections (by in large), the mainstream media has been asking that question. How could Americans be so stupid? The president himself has expressed that it's his failure to explain his genius to us (the common folk who cling insensibly to God and guns in fly-over states) that led to Republicans gaining 64 seats and a majority in the House of Representatives.
(graphic, h/t Dale)
American people have a difficult time reconciling themselves to socialism. They don't want nationalized anything because most of them find that the Federal Government can't run ANYTHING efficiently. Giving them control of healthcare (20% of the economy) means that they'll run it at a loss at twice the cost of allowing private enterprise to do it.
They just don't get it.