While neither snow nor rain nor heat nor gloom of night can stop mail deliveries, the Trump Administration certainly can. The Universal Postal Union (UPU) held an unprecedented emergency meeting in Geneva Tuesday, hoping to persuade Washington to stay in the 145-year agency that has thus far ensured uninterrupted international mail delivery worldwide.

If Trump pulls out of the union now, the impact on international mail could be abrupt and severe, insiders say. For example, military personnel and other Americans stationed abroad may suddenly find themselves unable to vote in U.S. elections. Retailers may not be able to deliver goods in the crucial Christmas season and beyond. People may find they can’t mail money or letters home in another country. Mail communications as we’ve always known them may end with other implications no one has yet turned attention to.

Mail is about more than carriers and postage stamps these days. Even the USPS uses complex technical systems -— there’s a reason Amazon uses them so much. The USPS system will be tough to outperform, even for a shipping company that’s already improved its technology.

“The departure of any country, first of all, is undesirable because no country has ever left the Union since 1874. This is the first time we have had this situation … Departure of the United States from the Union would mean a total destruction of the service. Because the moment any country leaves the treaty, that country does not exist,” said UPU Director General Bishar A. Hussein at the UPU third Extraordinary Congress Tuesday.

If the U.S. pulls out next month as it has threatened, then the UPU’s 192 member countries can’t exchange any letters, packets or parcels with the U.S. Postal Service (USPS) afterward. U.S. postal stamps will not be valid for the international mail system, and the USPS will no longer be able to use the UPU’s International Mail Processing Centre (IMPC) codes or any of its other services.

“One thing I want you to recognize is that this is a treaty-based organization. With one signature, when you enter the Union, you are a member; you have access to 192 countries. So, this means that the U.S. has to leave the union; it means it has to go and negotiate 191 different bilateral agreements with 191 countries, and you have to solve many other issues that have to be done bilaterally. This really affects their logistics, and global supply chain system,” Hussein explained.

“It’s also a nightmare scenario for the other side: All the other countries will not be able to exchange with the United States.”

After the UPU developed treaty-based rates in Istanbul in 2016 and agreed that the rates were to remain in effect until 2020, member countries returned to negotiate discounts and prices with their customers. But now that the Trump Administration has abruptly disrupted the plan, other member countries face angry customers who may protest by using alternate channels to deliver the mail to the U.S. or to other countries that must now ask for higher rates.

“For consumers it means big price increases,” Hussein explained.

Stamps.com’s Ken McBride

It could also cause the eventual demise of postal services in several countries, including the U.S. Privatizing the USPS has long been a Republican goal in the U.S. In remains to be seen if enough political will still exists to counter or prevent the U.S. from withdrawing from the UPU.

Indeed, private companies are already circling what they see as a fresh opportunity and moving closer to a competitive kill.

“We know customers simply can’t afford disruptions to their shipping services,” said Ken McBride, chairman and CEO of Stamps.com. “That’s why we’re proud to be able to offer these GlobalPost services to our many international shipping customers who have been concerned about the potential USPS disruption caused by …

… the breakdown of the UPU/U.S. relationship. As always, we’re trying to keep our customers a few steps ahead, especially when it comes to the ever-changing landscape of e-commerce shipping.”

For now, the world waits to see if Trump, now facing an impeachment inquiry, will carry through with his threat to withdraw the U.S. from the UPU over its rules that restrict rate increases he has said he wanted to impose on China and other countries. However, the U.S. indicated Tuesday that it may accept one of the UPU’s options that are currently on the table.

“Option B, I would say, is the preferred option for the United States. It would mean that every country has their own rates and the current system will fall. It will be everybody for themselves. It will mean bilateral arrangements,” explained Hussein.

Option B, which would allow countries to self-declare their rates from 2020, was rejected, with 78 countries voting against the proposal, 57 voting in favor and nine abstaining.

“But in a multilateral system like this, they do recognize that there are also other parties who are also members of the network. So, we have to find something that’s also comfortable for them. In my view, Option C was developed really to bridge the different extremes,” he added.

The Congress will resume to vote on Option C at 9 a.m. Geneva time Wednesday. That option would accelerate rate increases under the current remuneration methodology. It calls for phasing in optional self-declared rates between 2021-2025. However, if that proposal fails, then countries will vote on the proposal “closest to the status quo,” which is known as Option A. In that option, the current rate structure would continue “with accelerating planned rate increases aimed at moving all countries into a single rate system in 2020.”

President Trump has expressed similar desires for postal rate hikes inside the U.S. as well. Last December, he voiced outrage at Amazon’s shipping deal and by April a Trump-ordered review of the USPS was underway.

“Postal Service experts and even Mr. Trump’s own advisers have privately urged him to back off the accusations, noting that the huge number of packages shipped by Amazon is actually helping to keep the Postal Service financially solvent,” reported the New York Times.

Trump has repeatedly tweeted against Amazon, and subsequently its deal with the postal service, after being angered by negative reports about him in the Washington Post. He tends to use the hashtag #AmazonWashingtonPost in such tweets and often blasts Jeff Bezos, who owns both companies, which casts suspicions on his reasons to raise shipping rates specifically on Amazon.