Democrats enter the midterms with reasons for optimism. A historically unpopular Republican president, an American public unhappy with the rising costs of food and bills, and months of favourable polls all point toward a good night on Tuesday. Democratic candidates lead comfortably in well over the 218 seats needed to flip the House, and they are tied or narrowly ahead in key Senate races. Yet the party would be unwise to treat those numbers as a guarantee.
The track record is the problem. Polls missed Trump's performance in 2016 and 2024, and his narrow defeat in 2020 came after most surveys pointed to a more comfortable win for Biden. This year's primaries delivered their own shocks. Polling suggested Abdul El-Sayed was poised for a double-digit win in Michigan's Democratic Senate primary, but he finished 1%. In Wisconsin's Democratic primary for governor, a candidate with a lead approaching 20 points lost by a fraction of a percent. Those misses were not catastrophic, but in close races a few points decide who wins.
Clifford Young, president of Ipsos Public Affairs, offers a sober explanation. Pollsters struggle to reach Americans who have abandoned land lines and screen their calls, and many who are contacted refuse to participate. Young says conservatives, especially on the far right, are more anti-establishment and less likely to take part in anything. If Republican voters are systematically undercounted and pollsters fail to adjust their models, the data will lean toward Democrats. That is a warning, not a reassurance.
The historical pattern also cuts against an easy Democratic victory. Much of the contested territory Trump won easily in 2024, House boundaries now produce fewer switching seats, the electorate is more polarised with fewer swing voters, and Republicans hold a cash advantage for final-weeks attack ads. Democrats should focus on turning out their own voters and reaching undecided voters before election day, rather than assuming the polls have already settled the outcome.
Polls remain useful, but they are estimates with real margins of error, and the honest response is humility. Democrats should campaign as if the race is close, because in several key Senate contests it is. If they win, they should credit disciplined organising rather than a prediction. If they fall short, they should not blame the pollsters alone. Voters, not survey models, will decide this election.