CNBC reports that after Democrats' landslide in the November 2026 midterms, they plan to challenge Trump's tariffs through legislation reasserting congressional authority over trade, investigations into tariff exemptions, and a first-100-hours blitz, with the Canada trade war an early target. Their path is narrowed by the lack of a filibuster-proof Senate majority, Trump's promised vetoes, and multiple lawsuits already contesting tariffs, including the struck-down "liberation day" duties whose $166 billion in revenue is being refunded.