We have had three successive wave elections in the U.S.: 2006 when the Democrats captured control of Congress; 2008 when President Obama was elected and the Democrats swept Harris County; and 2010 when the Republicans recaptured the U.S. House and picked up 24 seats in the Texas House. Simplistically, a major factor in these wave elections is independents (the largest voting bloc in this country) swinging between voting for Democrats (2006 and 2008) and voting for Republicans (2010).
Combine this independent pendulum swing with what I consider to be the fundamental public policy maxim in this country today: Voters want services; voters do not want to pay for services. In 2010, the voter message was loud and clear -- do not raise my taxes and cut the size of government. But a recent UT/Texas Tribune poll asked voters what services they specifically wanted to cut, and the answer was essentially none of the above. According to pollster Daron Shaw, voters "really want to slash the budget, but not anything in it."
2010 was the election when voters stated they did not want to pay for services. I forsee 2012 as the election when voters state they want services. If I am correct, it could be yet another wave election -- but this time Republicans will be swept out to sea.