The latest item on Nate Silver's blog is headlined FiveThirtyEight Forecast: G.O.P. Senate Hopes Slipping and begins:
Democrats are now favored to retain control of the Senate when the new Congress convenes in January, according to the FiveThirtyEight forecast, breaking a summer stalemate during which control of the chamber appeared about equally likely to go either way.
He goes on to note that it's a volatile race and many outcomes are possible, but his forecast model gives Democrats a 70% chance of controlling the chamber.
Although this is the first time he has projected the Senate this cycle, he did some retrospective forecasting and the trends are fabulous:
Although this represents the first official FiveThirtyEight forecast for the Senate this year, I ran backdated forecasts to July 1 based on the polls that were available at that time. Two weeks ago, for example, the model would have given Democrats a 52 percent chance of retaining Senate control — and four weeks ago, it would have given them a 39 percent chance.
[Emphasis added.]
As most of you probably know, we currently control 53 seats. Assuming (as I do) that the President wins re-election, which would give Vice-President Biden the decisive tie-breaking vote, Republicans need a net of four pickups to gain control. And indeed, they are favored for pickups in the following four contests:
1) Nebraska
2) North Dakota
3) Montana
4) Wisconsin
But we are favorites for pickups in two contests:
1) Maine
2) Massachusetts
And as we all know other seats are in play on both sides. But I thought this was very encouraging news from Nate who is very disciplined in his prognostications, e.g., his electoral vote projections for the President have fallen from a high of 318.8 just nine days ago to 302.6 today.
As usual, the whole article is well worth reading.