LONDON — People in Algeria, Rwanda, Uruguay, China and Canada are now free to travel to parts of Europe on vacation. Travelers from the United States are not.

At first glance, it seems like the European Union has chosen a motley crew of 15 countries whose residents are now officially allowed nonessential travel into its member nations, something that has been restricted since the middle of March.

In fact, the Europeans say this exclusive club was devised using a strict set of epidemiological criteria.

That’s why the U.S. — which has the most coronavirus cases and deaths in the world — was nowhere near making the cut, according to three E.U. diplomats involved in the negotiations, speaking anonymously because they were not authorized to talk publicly about them.

“What do you think?” one of them deadpanned when asked if Washington had been close to meeting the threshold.

“The U.S. was never going to make it,” another said. “Just look at their coronavirus situation.”

So it’s no surprise that the list includes places lauded around the world for successfully tackling COVID-19, including New Zealand, Australia, South Korea, Thailand and Japan.

Despite recording more than 8,600 coronavirus deaths, Canada’s newly reported cases are decreasing and broadly the same as the European average, so it too made the list.

The club also features countries less renowned for their pandemic response: Tunisia, Uruguay, Serbia, Montenegro, Morocco, Rwanda, Algeria and Georgia, a nation which borders Russia and Turkey. But all of them satisfied the E.U.’s criteria.

China, where the outbreak is believed to have started, says it has had fewer than 400 cases in the past two weeks. It is the last country on the list, on the condition it allows entry to E.U. citizens in return.

A stark omission — from a political and economic perspective at least — is the U.S.

Effectively blackballing Washington will deny European cities the chance to cash in on hordes of lucrative American tourists, and risks a verbal clash between European governments and President Donald Trump.

During almost a month of talks, there was little if any suggestion that the U.S. might be included, the three E.U. diplomats said.

If that’s disappointing for American vacationers, it may be crushing for a European tourist sector that welcomes more Americans than almost any other country put together, according to the European Tourism Association, a trade body based in London.

“In 2019, for instance, we saw around 18 million U.S. visitors coming into Europe and they spent roughly 70 billion euros (about $78 million),” Tom Jenkins, the association’s CEO, said.

While Americans don’t tend to flock to Europe’s Mediterranean coastline in great numbers, Jenkins said they do dominate tourism for cities such as Paris and Milan — all of which will feel more pain following Tuesday’s decision.

The Europeans said that these economic considerations never entered into their discussions.

“If we started talking about making exceptions for countries that provide a lot of tourism, even if they have a lot of coronavirus cases, that would not be the right approach,” one E.U. diplomat said.

Asked about reports last week that the U.S. would likely be excluded from the final list, Secretary of State Mike Pompeo told a briefing that the U.S. had been working with its “friends in Europe and the E.U. proper to determine how it is we can best safely reopen international travel.”

While he said it was “very important” for the American and the European economies to reconnect, he didn’t want to reopen in a way “that jeopardizes the United States” and “we don’t want to cause problems for anywhere else.”

None of the European negotiators brought to the table specific countries they wanted to include, but rather outlined the criteria first before seeing which nations fit them, the diplomats said.

The first bar that countries had to pass was having equal or fewer new coronavirus cases than the European average, which stands at roughly 15 per 100,000 people over the past 14 days.

By contrast, the U.S. had around 145 cases per 100,000 people during that time, according to E.U. data — overshooting the threshold almost 10 times over.

As many as 54 countries passed that initial hurdle, according to a draft list seen by NBC News during the negotiations last week.

That was whittled down after the Europeans looked at whether each country’s infections were increasing or decreasing, and how reliable its government was on other issues, such as accurate reporting, testing, surveillance and social distancing.

For example, the central Asian nation of Tajikistan says its coronavirus infection rate is decreasing and is below the European average. So it made the initial list of 54 nations, along with India, Turkey, Cuba, Venezuela and dozens of others.

But according to that list, Tajikistan and many others have a relatively poor IHR score, relating to the International Health Regulations set out by the World Health Organization, which looks at a host of other factors related to a country’s health care system.

When all of these criteria were aligned, the final list of 15 was left standing, finally agreed to by E.U. ambassadors late Friday and confirmed and unveiled Tuesday.

An E.U. spokesperson declined to comment on why the extra criteria of reciprocity had been applied to China. But two E.U. diplomats involved in the negotiations said that this extra layer was included because of continued skepticism among some European countries about the hard-to-verify accuracy of China’s coronavirus data.

The final list means that any non-E.U. citizen living in a country that’s not on the list won’t be allowed in until the situation where they live changes. Exceptions include health care workers, diplomats, military personnel, or anyone with a family matter that they can prove is urgent.

But that’s not the end of it.

Already cracks in European unity are beginning to show with Italy, one of the countries worst hit by the coronavirus, saying within hours of the announcement it would opt out of the nonbinding list. Only members of the 26-member Schengen Area — which allows passport-free travel within Europe — will be allowed to go there, it said.

“The global situation remains very complex,” Italian Health Minister Roberto Speranza said. “We must prevent the sacrifices made by Italians in recent months being in vain.”