Despite Republicans losing some of their momentum from earlier in the year, control of the Senate is still roughly a jump ball.
This sentence from Nate Cohn in the New York Times is likely to thrill a lot of Republicans who hunger for good news about the upcoming midterms: “That warning sign is flashing again: Democratic Senate candidates are outrunning expectations in the same places where the polls overestimated Mr. Biden in 2020 and Mrs. Clinton in 2016.”
What was most memorable about the 2020 Senate polling were the spectacular misses — Sara Gideon’s consistent polling lead over incumbent Republican Susan Collins in Maine, and the Quinnipiac polls that kept showing South Carolina Republican Lindsey Graham tied with Democrat Jaime Harrison. Collins won by 8.6 percentage points, and Graham won by 10 points.
There were other smaller-scale examples of the same phenomenon, like North Carolina Republican Thom Tillis eking out a tight victory over Cal Cunningham, and Montana Republican Steve Daines winning by a comfortable 10-point margin after appearing tied or close to tied with Steve Bullock in many polls. In Iowa, a few late polls put Democrat Theresa Greenfield ahead by a small margin; Republican Joni Ernst won by 6.6 percentage points.
When Democrats won key Senate races, they usually – but not always – won by a smaller margin than the late polls indicated.
In the final RealClearPolitics average, Arizona Democrat Mark Kelly led by 5.7 percentage points; he beat Martha McSally by 2.4 points. In the final RCP average, Michigan Democrat Gary Peters led Republican John James by 5.4 percentage points; in the final vote Peters won by 1.7 percentage points. In New Mexico, pre-election polls showed Democrat Ben Ray Lujan leading Mark Ronchetti by 8 to 14 percentage points; Lujan won by 6.1 points.
In a few blue states, polling pointed to a gargantuan rout, and Election Day brought a more moderate rout. In Virginia, Mark Warner won by a lot – 11 points – but somewhat less than the 13 to 21-point margin that pre-election polling indicated. In New Jersey, Cory Booker’s reelection was never seriously in doubt, but he won by 16 points, not the 24 to 30-point margin that autumn polling indicated.
In Georgia, Democrat Jon Ossoff narrowly led incumbent David Perdue by seven-tenths of a percentage point; on Election Day, Perdue won by 1.8 percentage points, before falling to Ossoff in the runoff.
But in bluer territory, the final percentages lined up well with some consistent polling results. In New Hampshire, Democrat Jeanne Shaheen cruised to victory by a comfortable 15-point margin. In Colorado, John Hickenlooper beat Cory Gardner by a more-than-comfortable 9.3 percentage points. In Minnesota, Tina Smith led by all kinds of margins, but on Election Day she finished 5.3 percentage points ahead of Republican Jason Lewis.
Republicans would breathe easier if there was a nice, uniform rule like, “we’ll always perform three percentage points better than the final polling average.” Alas, past cycles suggest the polling industry doesn’t make conveniently undeviating mistakes. The polling averages are likely to be really off in some Senate races, moderately off in some others, and close to the final percentages in others – likely the least competitive ones.
A lot of this is common sense. Barring some unusual set of circumstances or significantly weaker-than-usual candidates, deep blue states tend to remain deep blue, and deep red states (like South Carolina) tend to remain deep red. Where you tend to find the biggest surprises are those swingier, purple states like Georgia, Maine, Michigan, and North Carolina – where a pollster underestimating or overestimating the turnout of either party by two to four percentage points could make up the difference in who is the projected winner.
When the Times applies its “what if the polls are wrong” formula to the current averages, the revised outlook for control of the Senate looks… awfully plausible: “The apparent Democratic edge in Senate races in Wisconsin, North Carolina and Ohio would evaporate. To take the chamber, Republicans would need any two of Georgia, Arizona, Nevada or Pennsylvania. With Democrats today well ahead in Pennsylvania and Arizona, the fight for control of the chamber would come down to very close races in Nevada and Georgia.”
Again, back in 2016, Wisconsin GOP senator Ron Johnson looked like toast throughout the fall – and somehow he managed to win by three points. This doesn’t guarantee Johnson will win this November against Mandela Barnes, it just means you shouldn’t count him out, even if his polling looks similarly bad in the coming months.
In Ohio, J.D. Vance is looking better, if not quite rock-solid. Republicans might want to keep an eye on North Carolina, which is not as Republican-leaning a state as it used to be. Trump won it by about three percentage points in 2016 and about a percentage point in 2020, and the state has a Democratic governor. The Tar Heel State is not an easy win for the GOP anymore.
Herschel Walker has led the last three polls in Georgia, albeit very narrowly. And in Nevada, Republican Adam Laxalt appears to be just barely behind Democratic incumbent Catherine Cortez Masto.
Despite Republicans losing some of their momentum from earlier in the year, control of the Senate is still roughly a jump ball.