By John Fund –
The conventional wisdom about who will control the Senate next year has sure taken a turn. Republicans were once rated a safe bet to win a majority, and as late as September 2 were given an almost 50 percent chance of doing so by statistician Nate Silver on his New York Times blog.
Now the rough patches in Mitt Romney’s campaign have combined with some good breaks for Democrats to push Republican chances for a majority down to 21 percent, according to Silver’s latest calculations. Left-leaning bloggers are already proclaiming liberal favorites such as Elizabeth Warren in Massachusetts and Tammy Baldwin in Wisconsin to be winners. But their euphoria is overblown.
A more sober reading of the polls shows only that the key races are volatile. Control of the Senate will hinge on a dozen states where the lead is likely to swing back and forth for weeks while remaining within the margin of error. This uncertainty is partly because pollsters have begun to survey likely voters instead of registered voters. About 35 percent of registered voters won’t turn out in November, so pollsters must try to identify which voters will actually cast ballots. Variations between polls often result from differences in the predicted partisan breakdown of the electorate. It makes a big difference whether a pollster predicts that the 2012 electorate will resemble the electorate in 2008, when Democratic turnout was relatively high, or the electorate in 2010, which included a greater number of Republicans.