Never waste a crisis.
This dictum of shrewd politicians everywhere has been enthusiastically implemented by Europe's growing clique of nationalist politicians since the summer, as migrants from Africa and then refugees from the civil wars of the Middle East began to arrive in the EU in record numbers. An estimated 800,000 have arrived so far this year.
They have used the migration crisis to strengthen themselves electorally - most recently in Poland, where a Eurosceptic, right-wing government replaced a pro-Europe centre-right one. Marine Le Pen's National Front has ridden fears about immigrants to make political gains in traditional Socialist Party regions in northern France.
Then came Friday the 13th in Paris.
The hard right in Europe is going to ride the wave of anger created by the atrocities that shook the world.
The dead were still being counted when Poland's new Foreign Minister, Konrad Szymanski, told a press conference in Warsaw: "The attacks mean the necessity of an even deeper revision of the European policy towards the migrant crisis."
Poland would no longer accept refugees without "security guarantees", Mr Szymanski added. What guarantees might satisfy his government he did not say.
But even before the Paris attacks, any kind of European consensus on the refugee situation was proving elusive.
In a classic case of bad timing, just as the attacks in Paris were just getting under way, German television showed an interview with Chancellor Angela Merkel, in which she despaired at the difficulty in finding "a way to share the burden fairly" in Europe.
The interview may have been granted to rebut the growing perception in Germany that the Chancellor has for the first time in her remarkable career misjudged the mood of her people with her call for Germany to be generous and take in as many as 800,000 refugees.
Certainly, she has misjudged the mood of her Christian Democratic Union party colleagues. Finance Minister Wolfgang Schäuble, discussing the situation last week, quipped, "avalanches can be triggered when a somewhat careless skier heads down the hill, shifting just a little bit of snow".
The remark was widely interpreted as being a criticism of Mrs Merkel. This in turn led to headlines about a CDU coup against the leader.
It has been a whiplash six months for the Chancellor. In the spring, as the Greek debt crisis reared up again, she was compared to Hitler in that country over her hard line on debt repayments.
In the event, Greece accepted another dose of bitter medicine and, in Germany and elsewhere, she was acknowledged as the most powerful person in Europe.
Late in the summer, as the refugee and migrant crises became acute, a crystallizing moment arrived: photographs of the body of two-year-old Aylan al-Kurdi, drowned, face down on a Turkish beach, flashed around the world.
Mrs Merkel immediately spoke out in favour of taking in refugees, and committed Germany to taking in 800,000 people fleeing Syria and Iraq. The Chancellor was no longer a Hitler figure imposing her will on Europe's weakest nation, now she was being portrayed as Europe's merciful angel.
But very quickly, right-wing, nationalist politicians began to push back and Mrs Merkel looked a lot less powerful.
A German plan with French backing to have EU member states take in refugees in proportion to their population size immediately ran into problems.
Hungary's Prime Minister, Viktor Orbán, a right-wing nationalist politician of the old school, became the voice of the refuseniks. "They are over-running us," he said. "They're not just banging on the door, they're breaking the doors down on top of us. Hungary is under threat and so is Europe."
Mr Orbán made his remarks shortly after a meeting among ministers from the Czech Republic, Slovakia and Hungary, at which the quota plan was discussed. Only three weeks had passed since the young boy drowned.
The Hungarian leader then underscored his words with actions. To get to Germany, the Middle East refugees had to pass through Hungary. Mr Orbán decided to block the refugee route into and out of his country.
Budapest's central train station began to fill up with refugees who had managed to get in but could not get out. Whether it was Mr Orbán's intention or not, pictures of large numbers of bedraggled refugees, many wearing traditional Arab clothing, soon supplanted the memory of the drowned toddler. "The Muslim hordes are at the gates" was the not-too-subtle message.
In the eastern reaches of the EU, where national historical narratives include battles against the Ottomans, there is a residual mistrust of Muslims. Hungary and other nations in the region were still fighting the Turks and Islam when the Enlightenment was well under way in England.
The Christian-Muslim conflict continued in eastern Europe until the beginning of what historians call the modern era.
But there are more contemporary reasons for Mr Orbán's successful appeal to xenophobia. Much of his part of the EU has not benefited from the globalising trends of the past two decades. Unemployment is high, acutely so since the crash of 2008.
It is not difficult to imagine people sitting in provincial towns looking at the pictures of thousands of people from the Middle East begging for refuge and saying no, we won't have "them". "Them", "they", were physically defined in glimpses in news photos but not known or understood. In a time of acute economic anxiety, these arrivals appear to be aliens who will drain a state's resources.
There is no way - forensically or academically - to characterise the refugees. It is a reasonable guess to think that they have some education if only because they have the financial means to pay the people traffickers to get them into Europe.
Anecdotally, that is the case based on the people known by this author who have arrived in Europe from Iraq this year. In the spring, a journalist acquaintance, in his mid-30s, who was forced to flee from Mosul to Erbil by a Daesh advance in 2014, left his family behind and set off for Germany.
He made it. In the summer, his wife and children, accompanied by his younger brother and his family made the same journey. By then, things were much more crowded, borders were being sealed and their trip was more difficult. The younger brother and his family are now in Finland.
Both men, and possibly their wives, are university educated. The man from Mosul is learning German. He understands the necessity of being able to communicate in the local language.
Noting this will not change minds in Hungary or Poland.
Even before Paris, the immigration crisis was causing an existential crisis for the EU. Two things define the evolved EU: the Euro and the Schengen Agreement. The former has been in crisis for several years, and Schengen is now in trouble as a result of the mass-migration.
Mr Orbán may have been playing to his domestic gallery when he sealed off his borders with razor wire, trapping and stranding refugees until everyone got a good photo of them, but the symbolism of those barriers resonated round the continent.
The Europe of free movement of goods and people - after half a century of hot and cold war - is arguably the greatest triumph of statesmanship in our lifetimes. The reappearance of barbed wire and closed borders as a response to the refugees is shocking.
In a statement as overtaken by events as Angela Merkel's comments on German television, the European Council President, Donald Tusk, said, the day before the Paris attacks: "Saving Schengen is a race against time and we are determined to win that race." He added a caveat: "Without effective control on our external borders, the Schengen rules will not survive."
Mr Tusk was speaking in Malta following a summit meeting of EU leaders to discuss the migrant problem.
Jean-Claude Juncker, European Commission President (there are too many chiefs in the EU; this may explain why effective action in any critical situation is difficult) had asked the national leaders to pledge €1.8 billion in aid for African countries, where so many of the economic migrants originate. In the end, around €78 million was pledged. Not likely to make much of an impact or convince the desperate ones making their way across the Sahara to rickety dinghies on Libya's Mediterranean coast to stay home.
Never waste a crisis.
The throat-slitters of Daesh understand that. That is what they are best at. Creating panic is what they do to gain territory. But they cannot hold on to what they have conquered when other fighters go at them. The Kurds have proven that at Kobani in Syria and now at Sinjar in northern Iraq.
In Paris, the intention, besides murdering for its own sake, was to create a crisis that would undermine government and, just as much, provoke a backlash against Muslims. Those disaffected Muslims, Daesh hopes, will sooner or later become sympathetic to their cause and decide to join them.
Aaron Zelin, founder of jihadology.net, tracks statements from Daesh command. In mid-September, at the time Mr Orbán was beginning his pushback against Mrs Merkel, Mr Zelin's website noted a video on a Daesh website titled, "Would you exchange what is better for what is worse?" Another video is addressed especially to those who fled the refugee camps of Turkey for Europe. "Why? You will only find injustice there," it says.
Mr Zelin writes: "The reality is, the Daesh loathes the fact that individuals are fleeing Syria for Europe. It undermines their message that its self-styled Caliphate is a refuge for them."
The best rebuttal to Daesh's argument is a generous welcome to those who have made it to Europe. But like so much else related to the crisis, the obvious choice is somehow the most difficult.
As you would expect, the Paris attacks have been swiftly followed by calls on the right in Poland, Switzerland, the UK and Bavaria, to scrap or amend Schengen, which is deemed unfit for purpose in the age of Daesh.
But while the death of Schengen might feel imminent, there are deeper political forces at work that mean it is still unlikely that there will be radical change, according to Mujtaba Rahman, an analyst at the Eurasia Group, the global risk consultancy. He points out that emergency border checks are allowed under Schengen - a facility that France is using, and which supporters of Schengen will argue is enough to protect states in times of crisis.
Second, Schengen has massive importance for the EU project. It speaks to the "essence of the EU" and, following the Paris attacks, France and Germany will be more determined than ever to preserve that open society.
But lastly - and perhaps most importantly - Mrs Merkel is fighting for her political survival. Giving up on Schengen would constitute a fatal blow to her hopes of creating pan-European asylum policy, further weakening the already-embattled German Chancellor.
"The French are keenly aware of this," says Rahman, "and I don't think have much to gain in this environment from a weakened Merkel. They need the refugee risk to be mutualised too. This will result in caution on Schengen."
