The sequence is the story, and both ends of it are documented.
The duties attached first. Section 301 tariffs of 10 and 12.5 percent apply to goods entered on or after 12:01 in the morning, Eastern time, on Friday July 24 [1]. Customs has been collecting them since.
The authority published second. The US Trade Representative's determination - 383 pages, document 2026-15181 - was filed for public inspection on Monday July 27 and publishes on Tuesday the 28th. The presidential memorandum of July 23 that stands behind it, document 2026-15274, was filed the same day [1].
Four days of collection before the legal notice reached the public record.
There is a partial mitigation and it belongs here: the determination carries an in-transit exception, so goods entered before 12:01 a.m. on July 28 are treated differently [1]. That protects cargo already on the water. It does not change the fact that the operative instrument was unreadable while it operated.
None of this is unlawful on its face. Effective dates that precede publication happen, and the Federal Register's public-inspection system exists precisely so documents can be seen a day early.
What is worth recording is the size of the gap and what was inside it: a 383-page determination covering 60 economies and 99.4 percent of US imports, in force for four days before anyone outside the government could read why.
