European Union leaders are meeting to debate how to end the migrant crisis before a second summer of chaos, but they have already long known the available answers -- and why they have yet to add up to a solution.
The political dilemmas of the crisis have had EU governments going round in circles for a year. This is how they go:
1. Mediterranean "Moat"?
Physical isolation from Africa, Asia and the Middle East has not prevented people reaching Europe. A fence built by Greece on its land border with Turkey in 2012 to condemnation from the EU was followed by more people using boats to reach Greek islands.
In late 2014, the EU scaled back naval patrols off Libya, arguing that rescuing people was a "pull factor" encouraging more to sail for Italy. But last April, the drowning of hundreds on one boat caused an outcry and rescue missions were restored.
Bound by the Geneva Conventions to offer at least temporary asylum to those saved in international waters, the Mediterranean has gone from being Europe's "moat" to a delivery channel for migrant smuggling gangs, in Libya and especially now in Turkey.
2. Ask the neighbours?
With neighbours like Libya? In fact, anarchy in Libya has seen a sharp drop in migrants going there to reach Italy.
The main route is now through Turkey. In November, the EU promised Ankara 3 billion euros to help 2 million Syrian refugees living in Turkey, revived EU membership talks and easier visas for Turks in return for stemming the flow. Lack of evidence that a winter drop is due to more than weather will be discussed with the Turkish premier at Monday's summit. At the same time, EU leaders' critics at home say they should not offer favour to President Tayyip Erdogan due to human rights concerns.
3. Fend them off?
Although the EU is now working on establishing a European Border and Coast Guard this year, and has enlisted NATO navies to patrol the straits between Turkey and the Greek islands, and although it threatens to attack smugglers, physically preventing people reaching safe haven is illegal and politically untenable.
4. Send them back?
Once ashore, the EU wants to send many migrants back. Easier said than done. Asylum claims can take years and fewer than 40 percent of those rejected actually go. It can be hard to know where to send them. Many countries refuse to take back their own citizens. Offering cash incentives, or strong-arm deportations are expensive and politically controversial.
The EU wants Turkey to take back people from Greece. But that is still being negotiated and it faces criticism that Turkey's human rights record does not make it safe for everyone.
This year so far, most arrivals have strong asylum claims: 44 percent of have been Syrian -- or at least say they are Syrian -- 29 percent Afghan and 18 percent Iraqi.
In any case, many experts argue that an ageing Europe needs more young people of the kind enterprising enough to reach it.
5. Lock them up?
EU leaders and voters are uneasy about the chaotic movements of migrants. Italy and Greece reject building "concentration camps" and detaining asylum seekers is legally problematic, even though they do not have a right to move to other EU states. Leaders are increasingly stressing that asylum seekers do not have a choice of where in the EU they can go. However, local communities are unwilling to host large reception centres.
6. Follow the rules?
Friction began years ago. Italy and Greece, frustrated at a lack of help from others, let migrants to travel north to richer states in defiance of the EU Dublin rules which say people must stay in the first EU state they reach and claim asylum there.
That had long eased pressure on the "frontline" states. But the northern reaction to last year's huge surge in numbers from Syria has led to new border controls across Europe. The EU is drafting new Dublin rules but that will be hard and take time.
7. Share the load?
New border controls across the passport-free Schengen zone threaten a cherished EU achievement and have poisoned relations to the point many fear for the future of the Union.
A plan to spread asylum seekers away from Italy and Greece and around the bloc according to national quotas prompted a furious backlash, especially in eastern Europe. Only 598 have been "relocated", angering Rome and Athens. Northern states say they have found it hard to find people willing to be relocated and say many prefer to make their own way to preferred cities.
That chaos has prompted more EU talk of forcing people to be relocated and that barring Greece's northern border, creating the current build-up there, will help kick-start relocations. It faces critics, however, who say people should not be coerced.
8. Check who's coming?
A big complaint of northern states against Italy and Greece was their failure to document, fingerprint and security screen those arriving. With EU support, "hot spot" processing centres have finally been largely set up. But Rome and Athens are still wary of holding people, for fear they will not then move on.
9. Make it legal?
One option being experimented with by the EU and favoured by Germany is to take the chaos out of the crisis by resettling genuine refugees directly from the Middle East to Europe, saving them risk and the cost of paying smugglers. There are legal and logistical hurdles to offering asylum to people not yet in the EU and some states simply oppose taking in any refugees anyway.
The resettlement option has now become a central bargaining chip in negotiations with Ankara, with Berlin trying to persuade Turkey that if it cracks down on people leaving for Europe via smuggling routes, the EU will take a share of refugees direct. Unless Ankara first shows results, however, any deal is on hold.
10. World peace and prosperity?
You know you have a big problem when fruitless circular arguments end up with ending poverty and war looking like the simplest answer. EU leaders have burnished their long-term programmes to promote economic growth in Africa that could help diminish the lure of Europe. And they are doing what they can to promote an end to war in Iraq and Syria. It is no quick fix.