US President Donald Trump [official profile] on Thursday waived [WP report] the Jones Act [text, PDF], a near-century-old law, easing shipping restrictions for hurricane relief to be sent to Puerto Rico.

The waiver was announced by White House Press Secretary Sarah Sanders in a tweet, which said: “At @ricardorossello request, @POTUS has authorized the Jones Act be waived for Puerto Rico. It will go into effect immediately.” The president himself later tweeted that: The electric power grid in Puerto Rico is totally shot. Large numbers of generators are now on Island. Food and water on site.”

This announcement comes after the Trump administration faced some backlash for the Department of Homeland Security‘s (DHS) [official website] statement on Monday that the law would not be suspended. Trump himself indicated that the law will not be waived [Huffington Post report] only Wednesday saying: “We’re thinking about that. … But we have a lot of shippers and … a lot of people who work in the shipping industry that don’t want the Jones Act lifted. And we have a lot of ships out there right now.”

The Jones Act was signed into law [NBC backgrounder] by late President Woodrow Wilson [official profile] at the end of the first world war. The act was passed as a protectionist measure in the 1920s, with a particular focus on competition from Germany. Specifically, it restricts domestic trade to US-flagged vessels managed by an American crew. Proponents say that the law protects American jobs and boosts national security because it reduces US dependency on foreign vessels, while opponents, including US Senator John McCain [official website], have called for its repeal stating: “It is unacceptable to force the people of Puerto Rico to pay at least twice as much for food, clean drinking water, supplies and infrastructure due to Jones Act requirements as they work to recover from this disaster.”

In addition to the waiver, the US has also dispatched USNS Comfort, a hospital ship that has responded to other natural disasters, to Puerto Rico.