In September 2019, after Trump tasked him with combatting China's usage of international mail rates to more cheaply ship products into the US, Navarro successfully led a diplomatic effort to the third Extraordinary Congress of the Universal Postal Union, where it agreed member countries could opt-in to self-declare their rates starting in July 2020. This agreement arose following repeated threats from the Trump administration to leave the UPU unless global postage rates were changed; at the summit, Navarro claimed that countries like China were unfairly benefitting from international delivery prices, particularly when it came to e-commerce deliveries.