06/10/2014 04:04 pm ET Updated Aug 10, 2014

The Syrian Conundrum: The Growing Threat of Returning Jihadi Fighters

President Obama recently expounded on his national security strategy at West Point by stating, "We don't have a choice to ignore what happens beyond our borders... As the Syrian civil war spills across borders, the capacity of battle-hardened extremist groups to come after us only increases."

While the Ukraine crisis and other important issues relegates Syria to the backburner of the global agenda, unabashed mayhem continues as Assad and his opponents fight to the death for control of their battered country.

With Assad's armed forces seemingly on the verge of military victory over the rebels, it is important to ask what will happen to the ever-increasing influx of jihadi fighters, from both Islamic countries and the West alike, once the rebel defeat is obvious.

Where will they go next? And to what extent will they give up fighting once back in their homelands? Will the returning fighters cut their ties to radical, al Qaeda-linked groups such as the Al-Nusra Front or the Islamic State of Iraq and Syria? Unlikely.

The failure of the Geneva talks is a stark indication that no political solution to the Syrian tragedy is in sight. Consequently, there will be no legitimate role for the opposition and its fighters in a post-conflict Syria.

On the contrary, the diplomatic standstill makes it abundantly clear that the regime change option is off the table. While the refugee crisis deepens and the killing continues, Assad feels strong enough to hold so-called "democratic" elections. To no one's surprise, the farce of an election ended in an overwhelming Assad victory, ensuring the devastating fighting will continue into the future.

Thus the return of jihadi fighters from the Syrian battlefield to Europe, and possibly North America, is increasing and will continue to grow. While one still wonders what triggered their radical turn, motivating these youngsters to leave behind a seemingly ordinary and somewhat comfortable life, the West needs to think hard about what to do with those who return.

This new phenomenon demands urgent attention. While the actual number of current fighters might not seem significant, it demonstrates an increasingly worrisome trend in warrior tourism. The EU Counter-Terrorism Coordinator, Gilles de Kerchove, warned that the number of fighters returning to Europe after their "tour of duty" is on the rise.

Research shows the number of fighters migrating from Western Europe to Syria tripled in 2013, with a high-end estimate of nearly 2,000 citizens fighting alongside the rebel forces. This number climbs to almost 2,700 fighters if the whole of Europe, North America, and Australia are included.

While one would expect fighters to primarily come from the conflict zones of southeastern Europe to include Kosovo or Bosnia, the number of Balkan fighters is only in the low few hundreds. The largest contingent -- totaling almost 800 fighters -- comes from Great Britain and France. An increasing number of Canadian and U.S. citizens are also joining their ranks.
This phenomenon first became visible during the bloody conflicts of the 1990s in former Yugoslavia, specifically in Bosnia. Jihadists from mostly Arab backgrounds fought on the side of the Muslim Bosniacs against Serb aggression.

It was a wise decision on the part of the U.S.-led Dayton negotiators to explicitly insist on the immediate repatriation of foreign mercenaries. Now the situation is even more complex and poses a novel challenge to Europe's domestic security.

While U.S. and EU officials are focused on the regional security fallout affecting Syria's neighbors, no comprehensive, integrated strategy to tackle returning jihadi fighters seems to be in place.

The long-term effect on European, and consequently transatlantic security, is largely unknown for now, but the threat is real. What happens when these fighters return home? Will they reintegrate into society or, more likely, fuel social, religious, and ethnic conflict?

It would be naive to assume that these "freedom" fighters will hammer their swords into plowshares. History teaches that unless they are dealt with in a constructive way, many will look for the next plot of fertile ground where they can put their newly gained expertise to use. Just last month, a French national murdered four staff members and tourists at the Jewish Museum of Belgium. Not surprisingly, reports indicate that the suspect spent up to a year in Syria where he fought alongside jihadist rebels.

In tackling this issue, it would be a big mistake, even counter-productive, to apply coercive measures or restrict basic human rights. A comprehensive strategy must be part of a wider effort to combat extremism and reduce the potential collateral damage from Syria.

Part of this approach needs to be close cooperation with Turkey and Lebanon, the main entry and exit points for jihadi fighters. No military solution, as dreamed of by Assad, or even fabricated elections, will bring peace to Syria.

The influx and eventual return of jihadis, equipped with lethal skills, is today's reality. It is time to do more than wave the red flag of concern. The short and long-term threat to Europe, and eventually to the United States, is evident and becoming more imminent every day.

Ambassador Wolfgang Petritsch was the European Chief Negotiator at the Kosovo peace talks in Rambouillet and Paris and the High Representative in Bosnia and Herzegovina. He is currently the Joseph A. Schumpeter Fellow at Harvard's Weatherhead Center for International Affairs.

Christopher Sage is a Colonel in the U.S. Air Force and flew combat missions over Bosnia, Serbia and Kosovo. He is currently a Senior Military Fellow at Harvard's Weatherhead Center for International Affairs.