What once looked like a secure Republican hold on the US Senate has become a competitive fight, with Democrats now contesting states like Texas and Iowa that were considered out of reach just a year ago. Driven largely by falling approval ratings for President Donald Trump — particularly on the economy, where an AP-NORC poll placed his approval at 32% in July — voters' dissatisfaction has complicated the landscape for Republican incumbents and candidates alike. Total advertising spending on Senate races is now projected to exceed $3.4 billion, with Republicans acknowledging the difficulty of the environment even as they maintain that the underlying electoral math still favours them.