“the U.S. Postal Service (USPS) will leave the Universal Postal Union (UPU) on October 17, ending 144 years of U.S. involvement”
tl;dr if you’re not a giant corporation, sendings stuff internationally will get prohibitively expensive and small businesses will falter
https://www.freightwaves.com/news/us-to-leave-global-postal-union-next-month