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The U.S. Postal Service proposed revising its international mail pricing system a few weeks ago. The new system would raise shipping rates from the United States by 13 percent on average. Seeing as foreign postal services deliver our mail overseas, do they get a cut of the postage?

Yes, but not directly. Say you’re paying the U.S. Postal Service 84 cents to send a letter to Paris. Part of that cost covers postal labor and infrastructure here in the United States. Another part takes care of the transportation to Paris. (The USPS regularly contracts commercial airlines, as well as private carriers like FedEx and United Parcel Service to transport international mail.) And a third part helps offset the fees paid to the French postal service to carry letters like yours from the airport to their destinations.

Since 1969, countries have been required to pay terminal dues to destination countries as compensation for local delivery costs. In general, they settle on the exact amounts every quarter based on both weight and number of items shipped. (Before this system took hold, countries just assumed that mail volumes were about balanced.)

Overseeing the terminal dues system is an organization called the Universal Postal Union, a Switzerland-based agency of the United Nations that standardizes shipping for its 191 member countries. Any member of the United Nations can join the UPU; other countries need a two-thirds vote from the member states to accede.

The UPU can even penalize member nations for late delivery. (Only developed countries are subject to penalties, plus a few developing countries that volunteer for extra scrutiny.) A part of a country’s terminal dues get docked if more than 86 percent of its incoming letters arrive late to their destinations. For most Western European nations, letters must arrive overnight after arriving in the country or they’re counted as late. In the United States, a letter’s lateness depends on whether it’s sent via overnight, two-, or three-day transit.

Before the UPU was founded in 1874, the international mail system was little more than a complex network of bilateral treaties. Senders had to arrange privately for every leg of the shipping. To send a letter to your cousin in Russia, first you might have to find someone you knew in France, who could forward it to someone he knew in Germany, and so forth. Some people even offered their services as “forwarding agents.” Look at old letters and you can see postmarks for each trip segment. Until the postage stamp was introduced in Britain in 1840, it was often customary for the recipient to pay shipping. As a result, unclaimed mail would pile up at post offices, because receivers didn’t want to or couldn’t pay. The arrival of postage made it easier for senders to pay a single fee at the beginning of the route.

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Explainer thanks Lea Emerson of the U.S. Postal Service and Allison Gallaway, Wilson Hulme, and Cheryl Ganz of the Smithsonian National Postal Museum.