U.S. blockade on sanctioned oil tankers tied to Venezuela faces enforcement challenges

The U.S. announced on Dec. 16 a measure to block or 'quarantine' sanctioned oil tankers tied to Venezuela; so far only a small number of vessels have been interdicted while multiple sanctioned ships have reportedly evaded enforcement.

The U.S. announced on Dec. 16 a measure described by the president as a "total and complete blockade" of sanctioned oil tankers to and from Venezuela, and other officials have called the action a "quarantine." The announcement followed U.S. sanctions tied to alleged illicit shipments and other charges against the Venezuelan regime. Legal scholars and former military lawyers have debated whether the term "blockade" is appropriate under international law, with some saying such an action is a wartime measure while others point to existing authorities to board stateless or improperly flagged vessels. Reported enforcement so far has been limited and the situation remains fluid. Key points: - Announcement: The president posted on Dec. 16 that he ordered a blockade targeting vessels on a U.S. Treasury sanctions list that are tied to Venezuela. - Legal framing: Administration officials have described the measure as a "quarantine," and some legal experts have said a blockade is conventionally a wartime naval operation, while others note a legal basis exists to board stateless or improperly flagged ships. - Enforcement to date: Two vessels have been interdicted in reporting — the Skipper was seized on Dec. 10 (before the Dec. 16 announcement) and the Centuries was boarded on Dec. 20 — and U.S. forces were reported to be planning an interception of another sanctioned tanker, the Marinera. - Evasion and effects: Multiple sanctioned tankers have reportedly evaded enforcement by masking location signals or sailing without known flags, and reporting says Venezuela's state oil exports have been disrupted as a result. Summary: The announcement has been followed by a mix of limited interdictions and reports of many sanctioned ships avoiding enforcement, and Venezuela's oil shipments have been reported as disrupted. U.S. forces were reported to be planning another interception, and the overall legal and operational outcome is undetermined at this time.