This is helpful to keep in mind - it should humble the new majority(ies?):
But none of this means that Republicans are winning. The reality is that voters in 2010 are doing the same thing they did in 2006 and 2008: They are voting against the party in power.
This is the continuation of a trend that began nearly 20 years ago. In 1992, Bill Clinton was elected president and his party had control of Congress. Before he left office, his party lost control. Then, in 2000, George W. Bush came to power, and his party controlled Congress. But like Mr. Clinton before him, Mr. Bush saw his party lose control.
That's never happened before in back-to-back administrations. The Obama administration appears poised to make it three in a row. This reflects a fundamental rejection of both political parties.
We're in a period of great volatility, which should dampen the meaning of any particular camp's victory.
I also wonder if the changes in the news cycle and news-delivery technology over the past 20 years have contributed to/exacerbated that volatility.