Half of the 50 US states have sued President Donald Trump and his administration over the global tariffs imposed in July, which include a 10 per cent duty on European Union exports. The 25 states argue the measures are as unlawful as those the US Supreme Court struck down in February. They rest on Section 301 of the Trade Act of 1974, which permits action against foreign practices judged to burden American commerce. The administration cited its own months-long investigation into failures to block imports made with forced labour. Trump then imposed temporary 10 per cent tariffs under Section 122 of the Trade Act.