IEEPA Tariffs — Deep Dive

Admitting goods to a Foreign-Trade Zone defers ordinary duties, but Section 301, Section 232, and IEEPA each reach FTZ merchandise in their own way. Deferral is not exemption.

Section 301, Section 232, and IEEPA each carry their own narrow, differently-shaped exit: an annex exclusion, a derivative carveout, a named exemption, or a Chapter 99 subheading that never applied at all. Part 7 of an 8-part series on Chapter 99.

Section 301 and Section 232 rest on completed investigations. IEEPA tariffs rest on an emergency declaration under direct constitutional attack — and even a winning challenge doesn't refund duty nobody preserved rights on. Part 6 of an 8-part series on Chapter 99.

IEEPA tariffs skipped the investigations behind Section 301 and 232. The Supreme Court held in 2026 that IEEPA doesn't authorize tariffs. Part 4 of 8.

The base HTS code changes once a year and is well-litigated. Chapter 99 changes on the timeline of the next proclamation, stacks three authorities that don't recognize each other's relief, and rests partly on a statute under active constitutional challenge. Part 8 of an 8-part series on Chapter 99.

Section 301, Section 232, and IEEPA duties don't offset, replace, or defer to one another — they stack, and an exclusion from one layer does nothing for the other two. Part 5 of an 8-part series on Chapter 99.

Chapter 99 is four titled subchapters, not one undifferentiated block of overlay codes — and nearly every current Section 301, Section 232, and IEEPA heading lives inside just one of them. A structural map read directly from the HTSUS text, heading range by heading range.

Chapters 1–97 classify products. Chapter 99 classifies policy — and it's bolted onto the HTSUS with different rules, a different update cadence, and a different failure mode. Part 1 of an 8-part series on Chapter 99.