Democrats think a blue wave is building. Here are 3 forces that could stop it

Senate Democratic Leader Chuck Schumer predicts Democrats are on the edge of taking back the Senate, citing favorable polling and voter frustration with higher costs under Trump and Republican control. The article outlines three forces that could stop a Democratic wave: a possible polling undercount of Republicans, weak favorability for the Democratic brand, and a large GOP advertising spending advantage. Trump, meanwhile, predicts Republicans will outperform expectations.