Nate Silver handicaps the November Senate elections and essentially comes up with the prediction I’ve been making for some time:
Our March forecast projected a Republicans gain of 5.8 seats. You’ll no doubt notice the decimal place; how can a party win a fraction of a Senate seat? It can’t, but our forecasts are probabilistic; a gain of 5.8 seats is the total you get by summing the probabilities from each individual race. Because 5.8 seats is closer to six (a Republican takeover) than five (not quite), we characterized the GOP as a slight favorite to win the Senate.
The new forecast is for a Republican gain of 5.7 seats. So it’s shifted ever so slightly — by one-tenth of a seat — toward being a toss-up. Still, if asked to place a bet at even odds, we’d take a Republican Senate.
which is that Democrats hold the Senate. How do I justify my claim? Because in real elections we don’t round. The number of seats gained is the number of seats gained and it will either be five (my prediction) or six and when you truncate 5.7 you get a five seat gain. For the Republicans to gain six seats it would more or less require them to run the table and I think the odds of that really aren’t that good whatever the polls say today.
There are things that could happen to change that. Democrats could foolishly seek to nationalize the election. The president’s approval rating could dip as a result of any number of things, e.g. deteriorating economy, one of the various scandals actually coming to a head, etc.
Since I don’t think any of those things will happen, I continue to believe that the Democrats will be weakened but will hold the Senate.