European governments are threatening to suspend Greece from Schengen, in what is the latest indication that the Schengen agreement, which governs free movement among 26 European countries, is eroding. On Dec. 2, several European officials told the Financial Times that Greece has been repeatedly warned and that if the country fails to improve border controls by a mid-December summit other Schengen members could impose border controls with Greece. This comes after Slovakia’s Prime Minister Robert Fico publicly called on Nov. 27 for Greece to be removed from Schengen. This threat may be a part of an ongoing negotiation process between the European Union and Greece, whereby the Greek government is seeking more significant financial assistance and concessions from the Europeans. Greece is also seeking to protect its sovereignty. Nevertheless, with some European countries already conducting border checks and the Schengen agreement slowly unravelling, some European governments may be more willing to follow through on this threat. A formal suspension of Greece could set the stage for an official breakup of the Schengen zone, either entirely or into smaller free movement zones.

Following the Nov. 13 attacks in Paris, European Union member states came to an agreement that focused on strengthening external borders and intelligence sharing. However, the ongoing refugee crisis, coupled with the impact of the terror attacks in Paris, has already led to temporary border controls across Europe. Germany, Sweden, Italy and Norway were among the countries that imposed at least temporary border checks over the past weeks. Many of these are ad-hoc, with deadlines for their removal unclear.

The threat of suspending Greece from Schengen comes at a time when the European Union is increasingly divided on the question of the future of free movement within the bloc. A group of European countries, including Germany, Belgium, Austria, the Netherland, Sweden and Finland, is considering a proposal to fly refugees who are currently in Turkey or other Middle Eastern countries to Europe. This voluntary resettlement plan, championed by German Chancellor Angela Merkel, would involve a so-called “coalition of the willing” that would implement the measures, a public recognition of the reality that the European Union is currently unable to come up with a plan that would be accepted and implemented by all member states. While the plan was designed as an incentive for refugees to apply formally while in Turkey for refugee status rather than attempt the trip to Europe on their own, a plan involving only a handful of European countries is unlikely to significantly ameliorate the crisis.

Regardless of whether the European Union follows through with its threat, increased discord among European states about border security and ways to address the ongoing refugee crisis will continue posing a threat to the future of Schengen, eroding one of the basic principles of the European Union: free movement.