The New York Times has just reported that the European Union is planning to bar travelers from the United States while allowing visitors from other countries, because the “United States has failed to control the scourge” of the novel coronavirus

Under this proposal, the United States would be lumped with countries such as Brazil and Russia, while travelers from China could be permitted to enter the E.U. It is not clear, however, how this list would work in practice. Here are the important things to know.

The list is not binding

The reason the E.U. might want to coordinate is that its current border policy is a mess. When coronavirus hit, the E.U. effectively stood aside as its member states introduced individual policies, including bans on travel from other E.U. countries. Now it wants to have some kind of common policy on borders within the E.U., which perhaps implies a shared policy on travelers from outside the bloc, to prevent people from entering a European country that has laxer controls and then being able to travel wherever they wanted.

However, the problem is that the E.U. doesn’t have much power to coordinate over health emergencies. A key proviso toward the end of the Times article says that “[t]he E.U. can’t force members to adopt it, but European officials warn that failure of any of the 27 members to stick to it could lead to the reintroduction of borders within the bloc.” What that means is that the list is a political set of recommendations rather than a legally binding decision that E.U. member states have to implement. Such recommendations can be politically important, since they set a standard that states can then be assessed by. But they can’t make states do anything that they don’t want to do.

The list is driven by European politics

Some U.S. commentators will read the U.S. exclusion from the list as a specific and deliberate political snub. That is almost certainly not true. While the negotiating officials are surely aware of how outside countries might respond, they appear to be more worried about creating unity among Europe’s member states.

As the Times describes the negotiations, they are focused on two lists of countries from which travel might be allowed. One list has countries that have a lower or the same rate of infection as the E.U. The other includes countries with slightly worse infection rates. This implies that the E.U. is basing the list on reasonably objective measures of the risks associated with allowing travelers to enter from different countries. The upside for U.S. travelers, again, is that the list is not binding. The downside is that the United States is in a bad position to press for an exception, as long as its rate of coronavirus infection is high.

The list is likely to cause fights within Europe

Even apart from the problems described above, the list is unlikely to shape European border control policy. Member states such as Spain want to reopen their borders to international tourism as quickly as possible, for economic reasons. Spain recently opened its borders to tourists from most of Europe, including Britain, where the coronavirus is still quite widespread, and is unlikely to want to be constrained by a nonbinding E.U. document. The Spanish government appears to be pinning its hopes on temperature testing and contact tracing to prevent the virus from becoming reestablished. Spain and other tourism-dependent economies may press for more openness.

There are bigger disagreements about travel within the E.U. The reason for continued border controls is that different countries have different rates of infection. In particular, Sweden has a much higher rate of infection than its neighbors, including another E.U. member state, Denmark. That is why Denmark has kept its border with Sweden closed while opening up its border with Norway, which is not a member of the E.U. This may mean that Sweden would like a list that could allow the reopening of borders but that its neighbors, which have been skeptical about Sweden’s unorthodox policy approach to the epidemic (it has placed only minimal controls on public interaction) will want to push back.

Finally, there might interesting politics in the relationship with Britain, which is still negotiating its departure from the E.U. The United Kingdom has relatively high rates of infection, and much closer ties to other member states than the United States does. It shares a border with one member state, the Republic of Ireland. British politicians might react badly if their country is blacklisted, leading to greater frictions in the negotiations over common border areas. In addition, the Republic of Ireland wants continued travel arrangements with Britain, because of political sensitivities over the border between Northern Ireland and the Republic of Ireland. Closing that border could hurt peace in Northern Ireland.

It is possible that countries in the Schengen zone, which covers most (but not all) E.U. countries plus Iceland, Liechtenstein, Norway and Switzerland, could come up with a shared approach. The Schengen zone used to allow effectively border-free travel among its member states. However, some of the most difficult problems include Schengen members that are unlikely to reach agreement easily (Sweden, Denmark and Norway are all Schengen members). And if there is no prospect of a return to border-free travel within Europe, it will be difficult to persuade member states to agree on a shared approach to travelers from outside the E.U.