Every two years, when I look at the fall polling in Senate races, I use the same basic framework, which I explained here and here:
First, I note that mid-September polls are typically not the last word in these races, which tend to move in a wave direction nationally, either in the direction of reflecting toward the president’s approval rating (in midterm years) or with the presidential race (in presidential years). Second, I look at the RealClearPolitics poll averages with particular attention to how far each candidate is from the magic 50 percent mark and what share of the remaining undecided vote would need to break in the Republican candidate’s direction to get to 50. I typically also flag how robust the data are for each race — how many polls make up each state’s average, and how many of those are relatively recent.
My approach is, I stress, a metric, not a model. I’m not making mathematical predictions or odds. I’m just collecting the data we have in one place, asking how much room there remains to move based on the current polling, and drawing from that some conclusions about what races are most winnable if one party or the other has the wind in its favor.
Let’s do a quick update. I last looked at the Senate polls two weeks ago. There are two weeks left in the race. How are things breaking?
For the first time in this campaign, we actually have one race that no longer has a clear favorite: the Ohio race between Sherrod Brown and Bernie Moreno, in which 55 percent of undecideds would need to break for Moreno to get him to victory. In every other race, one side or the other would still need to clear 60 percent. Pennsylvania, Wisconsin, and Michigan are all competitive races, but the Democrats are still visibly ahead. And even in Ohio, we have only one poll from the past two weeks, and it’s from Rasmussen, not the most reliable pollster. On the other hand, at this point it would require a fairly significant polling error for Ted Cruz or Rick Scott to lose.
If you look at the trend line since mid September, things become more optimistic for Republicans:
The races that have trended 1.8 points or better in the GOP’s direction over the past month read like a list of the presidential swing states, plus the top two red-state pickup targets: Nevada, Wisconsin, Ohio, Pennsylvania, Michigan, and Montana. Some of that is just the Senate races moving to converge with the presidential race, but it’s certainly not bad news for the overall fortunes of Republicans.