What is the difference between IEEPA tariffs and Section 301 tariffs on China?

“IEEPA tariffs (HTS 9903.01.xx) were imposed via executive order under IEEPA starting February 2025. The Supreme Court ruled these unconstitutional. Section 301 tariffs (HTS 9903.88.xx) were imposed under different legal authority starting in 2018. Section 301 tariffs are NOT covered by this ruling. See the documentation guide for full HTS code details.”