A proposal from Germany and Turkey to stop the uncontrolled flow of migrants into Europe could be marred by legal and political objections.

A deal reached on Monday would see Turkey take back migrants who have traveled to Greek islands. For every Syrian who is returned to Turkey, the EU would take a Syrian refugee from camps in the country.

Such a swap could involve hundreds of thousands at a time when European countries, especially Germany, are already overwhelmed by a record influx of people — and when the EU as a whole has managed to resettle just 3,400 asylum seekers under its existing scheme.

Demands

Turkey has other demands as well. It wants the EU to pay an additional €3 billion to help it shelter refugees from the civil war in neighboring Syria, lift strict visa criteria for its citizens and set aside the issue of Cyprus in its EU accession talks.

The EU promised financial aid and visa liberalization last year under a similar deal to little avail. The flow of people seeking asylum in Europe has continued unabated.

With the Greek and Turkish sides on Cyprus inching toward reconciliation, the island may soon not be an obstacle to Turkey joining the EU anymore. But there is little enthusiasm in Europe for Turkish membership. The issue of Cyprus — where Ankara has refused to recognize the Greek-Cypriot government in Nicosia — was always a convenient excuse to keep the Turks out.

Impractical

Legal experts have serious doubts about the proposal to swap migrants. International asylum rules stipulate that all applications must be properly considered. A blanket return policy could be illegal.

It is almost certainly impractical. Some 2,000 people land on Greek beaches every day. Officials struggle to fingerprint and register every migrant as it is. Many are impatient to travel on to richer countries in Northern and Western Europe. Forcing them back could get ugly.

Finally, the German-Turkish proposal will divide Europe. Angela Merkel, the German chancellor, wants a European solution to the migrant crisis. Many other leaders do not. She appears to have the support of the Dutch. The Danes and the Hungarians, by contrast, are wary.

Hungary and other countries in Central Europe previously opposed plans to redistribute migrants proportionately across the 28 nations in the EU. Germany’s neighbors Austria and Denmark have reimposed border controls inside the Schengen free-travel area.