President Trump signed the Countering America’s Adversaries Through Sanctions Act into law on August 2, 2017, targeting Russia, North Korea, and Iran. The law serves as a forceful, bipartisan statement that the US Congress continues to view robust economic sanctions as a foundation of US foreign policy, in which Congress will play a leading role in restricting trade, at times in conflict with the president’s authority to conduct diplomacy. The Russia portion of the law significantly expands the scope of the US sanctions regime and requires careful review by both US and non-US companies. The North Korea and Iran sections do not materially affect most US companies, which already face broad restrictions in those countries, but the North Korea section specifically includes additional secondary sanctions that create new risk areas for non-US companies.