US midterm polling uncertainty: GOP voters may be undercounted again

Recent polls show Democrats leading in both purple and deep-red states, but pollsters flag a persistent risk of undercounting Trump-aligned voters, as seen in 2016, 2020, and 2024. A modest polling error could flip control of Congress, making the actual outcome highly uncertain. This matters because market expectations of a Democratic wave may be overpriced if the GOP overperforms again.