Hurricane Maria has already wrought “apocalyptic” devastation to Puerto Rico, leaving many wondering how they can help. All living former presidents came together and are raising money to support relief efforts (donate here), but there is also a pressing governmental need to support recovery (this is a good place to remind everyone that Puerto Ricans are Americans; a bare majority of Americans know that Puerto Ricans are U.S. citizens, and support for aid increases when people are told that Puerto Ricans are citizens). This leads to all of the discussion about the Jones Act. But what exactly is it?

The Merchant Marine Act of 1920 was signed shortly after German U-Boats decimated American shipping during World War One. This law restricted “all trade between U.S. ports to American-flagged vessels crewed by U.S. citizens” because Congress wanted to protect the “merchant marine from foreign competition, so that the United States would have plenty of boats and able-bodied sailors at the ready in case the Germans came after the U.S. again in their submarines.” This means that foreign vessels are allowed to ship to Puerto Rico, but that goods sent from U.S. ports must be sent on ships that meet the Act’s specifications.

In the present day, some of its biggest advocates are “American shipping interests, which appreciate their monopoly on trade by sea between U.S. cities,” and its biggest opponents are “businesses — particularly energy firms — that would like to ship their goods on any vessel that’s available.”

If this sounds like a protectionist measure, that’s because it likely is, and groups like the Heritage Foundation have taken aim at the Act since well before Hurricane Maria was on anyone’s radar, arguing that it “has become the support system for domestic commercial shipbuilding.”

President Donald Trump suspended the act in the aftermaths of Hurricanes Harvey and Irene, and recently did so for Maria as well. This will allow goods to be shipped from U.S. ports without meeting the specifications required under the Act. While Puerto Rican officials urged a Jones Act waiver, another problem facing the island is the infrastructure damage, that is preventing around 3,000 crates of goods from being distributed. In fact, Senator Marco Rubio, who visited the island, said the “main problem” is overcoming the logistical problems on the ground.

The Jones Act waiver is certainly welcome news, but an influx of goods shipped to the island is meaningless if there isn’t a way to distribute them effectively.