Third problem: By June, as part of this deal, Turkish citizens will have the right to visa-free travel to the European Union. Around one-fifth of Turkey's population, some 15-20 million people, are Kurds. Since last summer, President Recep Tayyip Erdogan's government, having broken a two-year ceasefire with the separatists of the Kurdish Workers' Party (PKK), has been waging a pitiless war against them in the towns and cities of the southeast.
The only way to seal a frontier is to kill people who try to cross it illegally. The Iron Curtain worked pretty well, for example.
Some parts of Kurdish-majority cities in Turkey now resemble the war-ravaged cities of Syria. The Kurds, as Turkish citizens, will be able to enter most EU countries not as refugees but as tourists - and it would be very surprising if several million of them do not avail themselves of the opportunity. But the EU's goal in this deal was to stop the mass migration, not to change it from Syrian Arabs to Turkish Kurds.
In practice, things will never get that far. Long before the EU negotiators agree on the details of visa-free travel for Turkish citizens the deal will collapse - because it will automatically be cancelled if the number of returnees reaches 72,000. That's slightly more than one month's worth of migrants at the current rate of supply.
The goal behind this weirdly dysfunctional deal was twofold: to cut the total number of migrants drastically - more than a million made it into the EU last year - and at the same time to end the deaths that happen during the sea crossing: 460 drownings out of the 143,000 who tried to cross so far this year. But it simply will not work.
The only way to seal a frontier is to kill people who try to cross it illegally. After first few hundred deaths most people get the message and stop trying. The Iron Curtain worked pretty well, for example. But the EU isn't ready to do that yet - so how can it discourage migrants from making the crossing?
What if we ship almost all those who make it to the Greek islands back to Turkey, but promise to take one legitimate Syrian refugee out of the camps in Turkey for every Syrian we send back?
The Turks will go along with it if we give them $3.3 billion now, promise them another $3.3 billion later, and allow visa-free travel to the EU for Turkish citizens. The deal is win-win all round. What could possibly go wrong?
Well, there are around 2 million Syrian refugees in Turkey, and most of them are not even in camps. If they have a good legal claim for asylum, why should they wait in the queue? And if you are not Syrian - an Iraqi or Afghan refugee or an African migrant - where is your incentive not to get in a boat and try your luck?
To its credit, the EU has not yet deployed the ultimate argument: that refugees are already safe in Turkey, a country that is still technically a democracy with the rule of law, and therefore have no right to go asylum-shopping in greener pastures elsewhere. But after this new deal collapses, it will almost certainly come to that in the end.
Debate on this article is now closed.