The Senate races 29 October 2016

This is the next to last weekend before the election. Polling companies are paying close attention to most of the close races and the general trend is favoring the Democrats. Here is the graph of probabilities for how many seats the Republicans will hold in the Senate that convenes in January.

The most likely outcome is still a 50-50 split, with control of the Senate going to party that controls the White House. It is extremely likely that will mean Tim Kaine will be breaking any ties, as will be made apparent in tomorrow's post about the presidential race. But for the first time since any serious polling has been done, the second most likely outcome is for the Republicans to be in the actual minority.

Here's the lay of the land. There are 34 Senate contests, and 29 of them aren't close. In those races, it looks like the GOP are going to lose 3 of their 54 seats, bringing it down to 51-49 with five seats still closely contested.

The Republicans are on defense in four of the five closely contested races. If they win in Nevada, they could gain a seat. In every other close race, they can either stay at the current level or lose a seat. That means the optimal split for the GOP is 52-48 and the optimal for the Democrats is 47-53, barring major upsets. Here's the news on the five close races.

Nevada: Advantage Democrats, 55% to 45%
This race was advantage Republicans until this month. Now it is being polled by a lot of companies and of the last ten polls, five favor the Democrat Catherine Cortez Masto, four show a lead for Republican Joe Heck and one says it's a tie. It's about as small a lead as my system can create, but the momentum is in her favor.

North Carolina: Advantage Republicans, 66% to 34%
Of the "close" races, this is the least close. My system uses the median poll, and the ten polls currently being counted have seven in favor of incumbent Richard Burr. It would take a serious flurry of polls favoring his opponent Deborah Ross in the next week for this to change sides.

Missouri: Advantage Republicans. 55% to 45%
This race is unusual among the close five in that not a lot of companies have decided to do polling in Missouri. Trump's lead looks solid, but Roy Blount is in a contest, if we can trust the four polls taken this month. This is the only close race in a non-battlefield state. Go figure.

New Hampshire: Toss-up, 50% to 50%
Kelly Ayotte and Maggie Hassan are in a serious tussle. The last ten polls have four favoring Hassan, four giving Hassan the lead and two ties. Whoever polls better in the last week will get the advantage in my system.

Pennsylvania: Toss-up, 50% to 50%
Control of the Senate may very well come down to our all-Irish donnybrook in The Keystone State. In the last ten polls, Democrat Kate McGinty has the lead in four, there are four ties, and incumbent GOP Senator Pat Toomey leads in two. Again, the last week of polls will make a big difference, but the wind is at McGinty's back.  

Back tomorrow with more news about the long national nightmare that is Clinton vs Trump.