The Democratic Party enters the US midterm elections with high expectations, bolstered by a historically unpopular Republican president, public dissatisfaction with rising living costs, and months of favorable polling. Surveys suggest Democratic candidates lead in well over the 218 seats required to flip the House of Representatives and remain tied or narrowly ahead in key Senate races, including recent polls showing a tie in South Carolina and leads in Texas, Kansas, and Maine.
Polling Challenges and Voter Unpredictability
However, recent US political history contains numerous instances where public opinion surveys fell short. Donald Trump outperformed predictions in his 2016 and 2024 White House victories, while his narrow 2020 defeat followed surveys indicating a larger win for Joe Biden. Earlier primary season polls in Michigan and Wisconsin also missed actual outcomes by wide margins.
Clifford Young, president of Ipsos Public Affairs, told BBC News that polling has grown more difficult because declining landline usage and call screening make reaching Americans harder, while participation rates have dropped. “Conservatives, especially those on the far right, are much more anti-establishment by nature,” Young said, adding, “And they don’t participate in anything. They hate the system. That’s the challenge.” If Republican voters are systematically undercounted, it could skew survey data toward the Democrats.
One major factor in Trump’s past overperformances was the turnout of irregular supporters in higher-than-expected numbers. While midterm elections generally show greater polling accuracy—particularly because Trump is not on the ballot—tight margins in key Senate races mean a few percentage points can determine victory or defeat.
Historical Trends and Factors Favoring Republicans
Midterm elections typically favor the party out of power, as seen in 2010 when Republicans gained over 60 House seats amid a recovering economy and healthcare reform backlash. Although roles are reversed with Democrats currently in opposition, several factors suggest the party may not perform as strongly as history or low presidential approval ratings might indicate.
Much of the electoral territory in play was easily won by Trump two years ago, creating a home-field advantage for Republicans. Redrawn House boundaries have also reduced the number of switchable seats, while deep political polarization has resulted in fewer swing voters and a calcified electorate. Additionally, Republicans have maintained a cash advantage, spending hundreds of millions of dollars on attack ads in the final weeks.
While individual polls carry a margin of error, polling averages provide broader predictive accuracy. Polling inaccuracies can also favor Democrats, as seen in previous state and special elections where higher-than-expected Democratic turnout caused the party to outperform surveys. Trump’s final campaign rallies in states he won in 2024 have further encouraged Democrats, suggesting internal Republican polling may show conservative candidates facing difficulties.
Uncertainty remains right up until election day due to potential late shifts in dynamics or undecided voters breaking toward a single candidate. “I think we’re doing a better job,” Young said regarding modern polling methods, “But part of the problem we always have is not just with the pollsters. Part of it is that we’re dealing with humans. Humans are not easy.”
