From the Document: "In 2018, the U.S. Trade Representative (USTR) determined, pursuant to an investigation under 'Section 301' (Title III of the Trade Act of 1974, 19 U.S.C. §§2411-2420), that China's acts, policies, and practices related to technology transfer, intellectual property (IP), and innovation are unreasonable or discriminatory and burden or restrict U.S. commerce. To counter them and obtain their elimination, the Trump Administration imposed, under Section 301, four rounds of increased tariffs on approximately two-thirds of U.S. imports from China. However, to avoid harm to U.S. interests, the USTR instituted 'tariff exclusions' for certain U.S. imports that would otherwise be subject to tariffs. This is the first time that the agency has established an exclusion request process, and several Members of Congress have raised concerns about its implementation."
CRS In Focus, IF11582
Congressional Research Service: https://crsreports.congress.gov/