This week - from today, in fact - the deal made between the European Union and Turkey to stem the flood of refugees into the EU goes into effect. It will promptly blow up in everybody's face, for three reasons.
First problem: The EU won't be able to "process" the arriving migrants as fast as new ones arrive. Migrants are arriving on the Greek islands of Chios and Lesbos at the rate of almost 2000 per day, and as the weather improves even larger numbers will attempt the short sea crossing from Turkey.
Up to now the migrants have quickly been moved on to the mainland of Greece, but the Turkish-EU deal means that new arrivals will now pile up on the islands in detention camps while awaiting a decision on their asylum claims. Living conditions will become intolerable and there will be protests, some of them violent.
The EU has authorised a force of 4000 security and migration officials and translators to register the new arrivals and investigate their claims for asylum. Even if these officials had all arrived on the islands (most haven't), they wouldn't be enough. It takes time to interview the claimants, write up the claims, make decisions to accept or reject them, and even allow appeals - and meanwhile another 2000 will be arriving each day.
Second problem: Within one or two weeks the time will come for the first rejected asylum claimants to be sent back to Turkey. Having spent all their money and endured great hardships to get this far, they will not go back willingly. It will require physical force to get some of them on the planes or boats that will take them back - enough force that there will be casualties.