The deal that the EU is trying to seal with Turkey to limit the migrant crisis faces a number of problems including outright hostility from some states that could scupper an agreement.
Amid warnings that Ankara must not be allowed to “blackmail” Europe into a deal, here is a summary of the main sticking points at the summit on Thursday and Friday in Brussels.
Cyprus opposes a plan to open new chapters in Turkey’s long-delayed EU membership process, which the draft plan foresees “as soon as possible”, and has threatened to block the deal.
The eastern Mediterranean island has been divided since 1974 when Turkish troops invaded its north in response to an Athens-engineered coup attempt.
Turkey does not recognise the Cypriot government, and Nicosia has blocked six key chapters of Ankara’s negotiations for EU membership since 2009, effectively halting the process.
EU President Donald Tusk has suggested somehow tying in progress on efforts for a settlement between Turkey and Nicosia into the migration deal. The EU could also fudge language over the opening of chapters.
“It’s not a question of imposing on Cyprus the opening of a particular chapter,” an EU diplomat said.
2. Barely legal?
The UN and rights groups have warned that any mass expulsion of migrants from Greece to Turkey would breach international and EU law, posing a major headache for the European Union.
Under the deal Turkey would agree to take back all asylum seekers who arrive in the Greek islands after it is signed -- up to 2,000 are still arriving a day. In exchange for every Syrian refugee that is returned to Turkish soil, the EU will resettle one Syrian from camps in Turkey.
The EU’s insistence that the deal is legal rests on designating Turkey a safe country to which refugees can be returned -- something rights groups dispute.
It also rests on the EU saying that deportations are not “collective” because each migrant would have their asylum application, and any appeal, heard by special tribunals in the Greek islands.
EU lawyers have been batting different drafts of the agreement back and forth in recent days in a bid to iron out the issue.
The biggest threat is that the deal could be challenged in the European Court of Justice.
“The first thing that any judge would do if this issue was raised with them would be to raise it with the European Court of Justice,” a European legal expert said, adding that it could be suspended while the case was being heard.
3. Doubts on ‘one-for-one’
The so-called ‘one-for-one’ swap of Syrian refugees also faces objections from countries that rejected an earlier plan to redistribute 160,000 refugees from Greece and Italy around the EU. Fewer than 1,000 places have been taken up so far.
Brussels envisages relocating more than 72,000 refugees from Syria under the one-for-one deal. It would take 22,000 of those places from an earlier deal to resettle people from camps in Turkey, Jordan and Lebanon, while the other 54,000 would be taken from unused places in the 160,000-person relocation programme.
Participation would be voluntary for EU states under the plan.
But the failure to date of the relocation programme raises doubts that the new scheme could work.
4. Visa-free travel
Plans to offer Turks visa-free travel from June to the EU’s passport-free Schengen zone are controversial with many countries including France.
The European Commission insisted on Wednesday that all 72 criteria set by Brussels for Turkey to meet this condition must still be met -- a tall order as it includes the full introduction of biometric passports.
Many EU countries remain concerned about human rights in Turkey, especially after the government takeover of a leading opposition newspaper and President Recep Tayyip Erdogan’s escalating campaign against Kurdish separatists.
But with pressure from the migration crisis mounting, so far they have limited themselves to including expressions of concern in summit statements.