After a series of attacks by Islamic State militants, Turkey launched airstrikes against Islamic State targets in Syria for the first time. Its longstanding call for a buffer – or safe zone – along its border with Syria may finally become a reality. The purpose of such a zone is ostensibly twofold: to contain the violence in Syria from spilling across the border and to provide a cordon sanitaire of sorts, or “Islamic State-free zone,” for the hundreds of thousands civilians displaced from the fighting.

But Turkey’s latest push for a buffer zone has a less altruistic third aim: squashing Kurdish separatism. In addition to carrying out strikes against Islamic State targets in Syria, Turkey has begun a campaign of counterterrorism strikes against Kurdish separatists in Iraq, ending a two-year ceasefire.

The trouble is a buffer or “safe zone,” almost by definition, cannot simultaneously serve as a humanitarian corridor for displaced civilians and a free zone to strike suspected militants with impunity. A buffer zone would in effect create a kind of legal no man’s land without guarantees in place to prevent such a “safe area” from becoming a target for the Islamic State or Syrian forces but also for Turkish airstrikes. This is likely to jeopardize civilian safety and escalate cross-border violence, and it has the potential to make an already perilous humanitarian situation worse.

There is a precedent for such a zone – a similar one existed between Iraq and Turkey during the Iran-Iraq war before Saddam scotched the idea in 1988. Jordan has floated the notion of a similar buffer zone stretching from Suwayda to Deraa in the south. Yet, the Turkish buffer zone proposal enjoys little support outside Turkey. The United States fears it would needlessly escalate the conflict by providing a vacuum for extremist groups like the Islamic State to fill and drawing in more outside powers as parties to the Syrian conflict. There are also concerns that a buffer zone would allow Turkey to either deport or refuse entry to refugees since, in theory, they would now have a safe area in Syria.

The strategic value of a buffer zone makes sense. If states, as realists suggest, are like a cluster of “billiard balls” colliding up against one another with few shock absorbers or room to maneuver, aside from, say, the stopping power of water, then in theory a buffer zone should provide countries with more cushioning and reduce security dilemmas. There are at least a dozen such zones around the world – some formalized, others de facto – including in Cyprus, the Sinai Peninsula and Moldova’s Transnistria region. The idea of installing buffer zones has crept into other conflicts. During recent negotiations, Russia and Ukraine called for a 15-kilometer buffer zone along Ukraine’s eastern border from which both sides had agreed to withdraw heavy armaments.

The trouble with such zones is precisely their ambiguity. Since states are legally forbidden from militarily entering another state’s territory in the absence of an armed attack, a buffer zone might allow governments to pursue rebels or terrorists without technically violating their neighbor’s sovereignty. Consider apartheid-era South Africa’s buffer zone in Namibia, which was instituted as a shield against the war in Angola from spilling over, as well as a way to pursue separatist rebels. Despite the presence of a buffer zone in the Vietnam War, U.S. forces pursued the Viet Cong into North Vietnam in the late 1960s. U.S. officials accused Russia-backed rebels of violating its ceasefire agreement with Ukraine by moving air-defense systems into the agreed-upon buffer zone.

Other zones have not only failed to achieve their aims – such as the demilitarized Rhineland after World War I or Egypt’s notoriously porous buffer zone with the Gaza Strip – but arguably made the situation worse. Neither buffer zone enhanced the security of either the local residents or the neighboring states. Moreover, the physical creation of a buffer zone can require drastic and punitive actions to implement. To install such a zone along the Angolan-Namibian border, South African forces killed livestock, poisoned wells and blocked the distribution of food. Likewise, over the past year, Egyptian authorities have razed hundreds of homes to enlarge their buffer zone along the Gazan border. Worse, buffer zones can create the false impression of security and stability during a war in which zones of control are actually often fluid – the UN-patrolled “safe haven” in Bosnia created the conditions for the 1995 Srebrenica massacre.

Of course, not all buffer zones have failed. The Golan Heights has effectively shielded the violence in Syria from spilling into Israel. Despite occasional flare-ups in fighting, the demilitarized zone between the Koreas has held for more than half a century. But the buffer zone Turkey has in mind for Syria would escalate the conflict, not deescalate it.

Since the start of the Syrian war, Turkey has accused Syrian President Bashar al-Assad of providing the largest Kurdish opposition group in Syria, the Kurdish Democratic Union Party, or PYD, and its armed forces, the People’s Protection Units, or YPG, safe haven and indirect material support in hopes that the group takes its fight across the border into Turkey. The YPG is loosely an affiliate of the Kurdistan Workers Party (PKK), which is based in northern Iraq and which has waged a decades-long civil war against Turkey for greater autonomy. Syria sought to punish Turkey both directly (through airstrikes) and indirectly (supporting Kurdish rebels) for assisting Syrian opposition groups and drive a wedge between its Kurdish communities and other rebel forces. Turkey’s then-Prime Minister Recep Tayyip Erdogan warned Syria in 2012 that his government would “not stand idle” in the face of cross-border incursions, and “is capable of exercising its right to pursue Kurdish rebels inside Syria, if necessary.”

The push for a buffer zone in Turkey is borne less out of fear of the Syrian civil war spilling over the border than fear that Syrian Kurds, who comprise 30 to 40 percent of the population of northeastern Syria, might defeat the Islamist and government forces in the north and establish a safe haven from which to carry out cross-border attacks against Turkey. Such a scenario would be a mirror image of the Kurdish insurgency in Iraqi Kurdistan. The establishment of a buffer zone would allow Turkey more legal wiggle-room to intervene in Syria as it could use the pretext both of self-defense and humanitarian concerns.

The surge in Kurdish-related violence killed some 700 people during the first 14 months of the Syrian conflict, according to the International Crisis Group, including a car bomb that killed nine in Gaziantep blamed on Kurdish rebels. Turkey thus found itself in the awkward spot of aiding rebels whose ranks include untold numbers of Syrian Kurds who could take up arms against Turkey were the Assad regime to fall (Syria’s Kurds reportedly had struck deals with opposition forces and the Syrian government as a way to both hedge its bets and remain semi-autonomous). In this way, the buffer zone Turkey is calling for along the Syrian border, not unlike the U.S.-led no-fly-zone imposed over Northern Iraq in 1991 to halt flows of Iraqi Kurdish refugees, might actually provide Kurdish militants with greater cover to carry out cross-border attacks in Turkey.

While a zone could prevent direct spillover of fighting into Turkish territory, it could also prove a slippery slope into the Syrian civil war. The only party that can likely be coerced to adhere to the zone would be the Assad regime, whereas both Kurdish militants and especially the Islamic State are unlikely to be deterred. Their de-facto foothold in the region that would be included in the buffer zone would make the provision of security within its demarcation extremely difficult.

In addition, it seems likely that the Islamic State in particular would try to probe the effectiveness and implementation of the zone through raids or terrorist attacks. This would in turn necessitate retaliatory strikes, which could spiral into a de-facto intervention against every single party in the Syrian civil war. Overt strikes against the Kurds, however, would mean that Turkey could quickly lose Western sympathies. Turkey’s fears of a Kurdish state on its doorstep are not unfounded. But its policy to date of turning a blind eye to Islamist fighters streaming across its border while taking a hawkish stance against Kurdish rebels is misguided and likely to backfire. A safe zone in Syria makes sense only if its aim is to protect displaced civilians, not to carry out counterterrorism strikes against Kurdish separatists.

Lionel Beehner is an instructor at the U.S. Military Academy of West Point’s Modern War Institute and doctoral candidate at Yale University. The views presented are those of the authors and do not necessarily represent the views of the Defense Department, the Army, or any of its subordinate commands. Gustav Meibauer is a doctoral candidate at the London School of Economics and Political Science.