For more than four years, Americans and Europeans have largely stood by as Syria descended into a violent and bloody civil war. Only when the conflict started spilling out into Iraq did the United States step in and start to try to contain ISIS—albeit largely from the air.

Starting early this summer, Europe began to more acutely experience fallout from the war. The refugee crisis, which has been in large part driven by the steady flow of asylum-seekers from Syria, has put the Schengen joint border management regime under unprecedented stress. Its unraveling threatens free movement inside the EU—one of the key achievements of the European project. Large parts of Europe refuse to take in war refugees, and right-wing parties are on the rise across the continent. And now the latest blow: the attacks in Paris were apparently masterminded in Syria, with at least some of the perpetrators trained and indoctrinated there.

It should be obvious that it will be impossible for Europe to live in peace and tranquillity when a whole region in the immediate neighborhood goes up in flames—when a so-called government, various warlords, and terrorists fight a ruthless, bloody war of attrition, killing hundreds of thousands of people, destroying infrastructure and shredding a country’s social fabric to tatters. Europe cannot just keep on watching and hoping that the fighting ends. Or can it?

True, France wants a stronger military response, and is in the process of building a coalition to fight ISIS that would include Russia. Answering France’s invocation of a little-known mutual defense clause of the EU Treaty, a number of countries are considering giving some support the French effort, but more out of solidarity with France and than out of conviction.

In Germany, today widely seen as the leading country in Europe, there is not much debate about Syria and even less about what could be done to end the war. The debate about refugees has been instead focused on questions of identity—how much immigration can German stand? A recurring criticism of Merkel from center-right media has been that the chancellor allegedly wants “another Germany”, a more multicultural country.

And after the Paris attacks, the debate about a potential connection between the influx of refugees from the Middle East and terrorism has intensified, at least on the right of the political spectrum. But almost no political leader or commentator argues that Germany should address the root cause of the problems in the Middle East, in Syria, by fighting ISIS. The German consensus is, as foreign minister Frank-Walter Steinmeier has said, that there is no military solution to the war in Syria.

While it is true that just throwing more bombs on ISIS will not make much of a difference, it is also true that the peace process being hashed out in Vienna, which in the words of U.S. Secretary of State John Kerry is based mainly on “hope”, is unlikely to solve much either. The hope is that all the various players will come to an agreement that it is in everyone’s interest to end the war, stick to it, and convince their various clients on the ground to play ball. Why should they do now what they refused to do in the preceding four years?

The containment strategy, devised and implemented by the U.S., has failed to protect Europe from the fallout of the war. Getting beyond mere hope requires a concerted effort and commitment by the West to end the fighting. The U.S. and its European allies would have to exert serious pressure on all the players involved, including Russia, Iran, Turkey and Saudi-Arabia. They would have to invest massive resources into the effort, including military ones, committing themselves to a long and painful slog, in both enforcing a power-sharing agreement, and then guaranteeing its faithful implementation.

But almost none of the Western powers (with the potential exception of France) are ready to do that. They are not ready to fill the vacuum that the destruction of state and society has left in Syria, the space that is now being filled by Assad’s henchmen and an assortment of jihadists. The U.S. wants, at almost any price, to avoid anything that resembles the painful Iraq experience. A major state-building project in the Middle East is something that President Obama, who has made ending wars a cornerstone of his legacy, is very unlikely to start. And most of Europe, which is much more directly affected by the breakdown of order in Syria, is opting to shield itself from the war’s collateral damage rather than addressing it head-on.

“Hope”, then, is what everything hangs on: hope that the war will somehow magically burn itself out, hope that ISIS won’t be able to strike again in Western capitals, hope that Europe can cope with the stream of refugees without losing its precarious internal balance. If this hope-based strategy somehow works, we would be right to call it a miracle.

But a much darker scenario is possible, and if nothing is done, increasingly likely. A never-ending stream of refugees will lead to an increasingly bitter fight between EU countries over borders, immigration and asylum law. Key elements of the EU system of governance, such as the free movement of people, will break down, borders will be reinstated, and much of the trust that has been built up over the last decades between Europeans will be forgotten. Large parts of the population will increasingly vote for xenophobic, far-right parties—parties that make false promises of protecting nervous voters from the the downsides of globalization while vowing to preserve all of its advantages. Additional terrorist attacks will spread fear and sow more discord across Europe, even as draconian anti-terror laws and operations gnaw away at civil liberties.

Both the festering refugee crisis and the brutal attacks on Paris must be seen as proof of the saying “nature abhors vacuum”. The vacuum of governance in Syria and parts of Iraq has been filled by malevolent, dangerous actors. For years Europe could live in the illusions that it wouldn’t be affected by this war.

Now the war has come to Europe. It is time to get real and to start a major effort to end this war. A half-hearted diplomatic process won’t be enough.