Jones Act

The Jones Act, formally the Merchant Marine Act of 1920, requires that goods shipped between US domestic ports must be transported on vessels that are US-built, US-owned, US-crewed and US-flagged. The law has been a persistent constraint on US energy logistics, most visibly during supply disruptions when the fleet of qualifying tankers is insufficient to meet domestic demand and temporary waivers are required.

On 18 March 2026, President Trump signed a Jones Act waiver as one of two Iran-related presidential instruments across 45 days of war. The waiver authorises foreign-flagged tankers to move petroleum products between US ports, a measure designed to contain domestic fuel price rises as global oil markets tightened during the early weeks of the Iran conflict. It was paired with an authorisation for Venezuela's PDVSA to resume sales to American refiners.

The Jones Act waiver is the only signed presidential instrument related to US energy supply policy since the blockade of Hormuz began. The blockade itself, the Ceasefire declaration and five Hormuz ultimatums all rest on social-media posts rather than signed directives, creating a stark contrast between the careful paperwork of the Jones Act waiver and the informal legal basis of the military operation it was designed to support economically.