For four years, a bloody war has raged in Syria. What began as a democratic uprising against Bashar al-Assad’s dictatorship has developed into a cat’s cradle of conflicts, partly reflecting a brutal proxy struggle among Iran, Turkey, and Saudi Arabia for regional domination. This struggle, as the fighting in Yemen has shown, has the potential to destabilize the entire region. And now Russia, by means of its military intervention on Assad’s behalf, is seeking to enhance its status as a global power vis-à-vis the West (and the United States in particular).

So the conflict in Syria is taking place on at least three levels: local, regional, and global. And, because the fighting has been permitted to fester and spread, around 250,000 people have died, according to United Nations estimates. This summer, the UN Refugee Agency put the number of refugees who had fled Syria at four million, in addition to 7.6 million internally displaced people. In the meantime, the flow of Syrian refugees to Europe has developed into one of the greatest challenges the European Union has ever faced.

The Syrian civil war has also become one of the most dangerous breeding grounds for Islamist terrorism, as the Islamic State (ISIS) attacks in Ankara, Beirut, and Paris, and the bombing of a Russian passenger plane above the Sinai Peninsula, have shown. Moreover, Turkey’s downing of a Russian warplane has heightened the risk that major powers will be drawn directly into the fighting. After all, Turkey, as a NATO member, would be entitled to the Alliance’s military assistance were it to be attacked.

For all these reasons, the Syrian war must be brought to an end as quickly as possible. Not only is the humanitarian disaster worsening almost on a daily basis; so are the security risks emanating from the war.

Following the November 13 terrorist attacks in Paris, a new opportunity to end Syria’s agony has emerged, because all the important players (except ISIS) are now willing to sit down together at the negotiating table. But, although all players have agreed to fight ISIS first and foremost, the big question remains whether they will in fact do so.

The Kurds in northern Syria and Iraq are the most effective fighters against ISIS, but their own national ambitions put them at odds with Turkey. Iran and Saudi Arabia are fighting primarily against each other for regional predominance, relying on non-state actors. Russia is fighting for global status and against any form of regime change.

Russia thus finds itself allied with Iran in supporting Assad’s dictatorship, while Iran, in turn, is pursuing its own geopolitical interests by backing its Shia ally in Lebanon, Hezbollah, for which the Syrian hinterland is indispensable. France is more serious than ever about fighting ISIS, while Germany and other Europeans feel obliged to assist it – and to stem the flow of refugees emanating from the region.

The US, meanwhile, is operating with handbrakes on. President Barack Obama primarily wants to avoid involving the US in another Middle East war before the end of his term. With the main global power remaining on the sidelines, however, the inevitable result has been a highly dangerous power vacuum, which Russian President Vladimir Putin is seeking to exploit.

In particular, because the US refuses to lead and Europe is too weak militarily to influence developments in Syria on its own, there is a threat of a de factoEuropean alliance with Putin’s Russia. That would be a grave error, given that any kind of cooperation with Russia wouldn’t contain or end the war in Syria: In fact, there is reason to fear the opposite: Any military cooperation with Assad – which is Putin’s aim and price tag – would drive a large majority of Sunni Muslims into the arms of radical Islamists.

Such a tendency is already visible in Iraq. The Shia-dominated government of former Prime Minister Nouri al-Maliki played a decisive role in radicalizing Iraqi Sunnis and convincing them to support ISIS. It would be extremely stupid to repeat the same mistake willfully in Syria. Indeed, striking such a bargain would have nothing to do with realpolitik, because the war in Syria cannot be ended with either ISIS or Assad still in the picture.

Any Western collaboration with Russia must avoid two outcomes: the linking of Syria with Ukraine (the negotiations with Iran on limiting its nuclear program succeeded without such a linkage) and military cooperation with Assad. Instead, an attempt should be made to link a military intervention against ISIS, conducted under the auspices of the UN Security Council, with an agreement on a political transition process that moves from an armistice to a national unity government for Syria and the end of the Assad regime.

And there are other big challenges looming beyond Syria: Iraq’s descent into chaos, closely linked to the Syrian tragedy, threatens to turn into a new theater of conflict between Iran and Saudi Arabia. Unless this fight for regional hegemony is contained, further proxy wars – with all the risks they entail – are inevitable.

Ultimately, the decisive battle with Islamist extremism will take place within the Sunni community. Which form of Sunni Islam will prevail – the Saudi-Wahhabi version or a more modern and moderate one? This is the decisive question in the fight against ISIS and its ilk. In this context, an important factor will be how the West treats its Muslims – as welcome citizens with equal rights and obligations, or as permanent outsiders and fodder for jihadist recruiters.

Joschka Fischer was German Foreign Minister and Vice Chancellor from 1998-2005.

Copyright: Project-Syndicate.