In 1995, the Turkish army invaded northern Iraq, sending some 35,000 soldiers across the border to destroy the guerilla infrastructure of the Kurdish Workers Party (PKK) a militant group made up of Turkish Kurds that had found refuge in the lawless mountain region. Operation Steel, as it was called, killed over 500 militants, but still the PKK survived to fight another day. In early 1997, the Turks sent in another 30,000 soldiers — this time as part of Operation Hammer — to finish the job. They didn't. The Turks had to go in again later that year with Operation Dawn.This month the Turks launched yet another operation against the PKK, and there is little to suggest that it will be any more effective than the others. So far 300 Turkish commandoes crossed briefly into Iraq, while Turkey has staged three air strikes, including one Wednesday. Turkey claims to have attacked some 200 PKK locations, and killed hundreds of militants. A PKK fighter told TIME that just five of the group's members had been killed. Whatever the true figure, the operation would seem to be a minor chapter in Turkey's seemingly never-ending civil war with radicals among its oppressed Kurdish minority population, who took up arms in the 1980's.This time however there are some important differences. Turkey isn't invading the lawless hinterland of a pariah nation (Saddam's Iraq) but a region that not too long ago was considered the one relative success of the American project in Iraq. The United States — which controls Iraqi airspace — tried to forestall a Turkish invasion, but eventually caved into Turkish demands and agreed to a limited incursion. The fact that Turkey was ready to risk alienating its American ally for an operation with little chance of strategic success is a testament to the uproar by the Turkish public for action against the PKK. But it is also a troubling sign of the role that Turkey will play in Iraq as American power recedes.Turkey has long been hostile to the emerging power of Iraq's Kurdish minority, located primarily in northern Iraq. Concerned that Kurds might take control of the oil rich Iraqi city of Kirkuk, Turkey inserted itself into Iraq's domestic political problems by dubiously claiming stewardship of Kirkuk's minority Turkoman population (with whom ethnic Turks share a distant Central Asian past and little else.) More recently, Turkey has demanded that Iraq's Kurds rid northern Iraq of the PKK, a job that the government-sanctioned Kurdish peshmerga militias are unable to do. The peshmerga are currently overstretched in Baghdad and Mosul trying to keep Arab insurgents from entering Kurdistan. (Iraqi Kurds tried to expel the PKK in the 1990's, but, like the Turkish army, they failed.)Now, Iraqi Kurdish leaders say that Turkey's unwillingness to open peace talks with the PKK, and its adherence to failed military policies, is a sign that Turkey is using the PKK as excuse to threaten Iraq's Kurds — and to scare them from even thinking about declaring an independent state. Whatever Turkey's intentions, the latest Turkish operation has reminded the Kurds of Iraq just how much their newfound safety and autonomy depends on American protection.Kurdish leaders in Iraq have been relatively subdued since the Turkish operations began, acquiescing perhaps to the fickle will of their American masters. They know better than anyone that, without American protection, it's doubtful their hostile neighbors — not just Turkey, but also Iran and Syria, which have restive Kurdish minority populations of their own — would limit themselves to a few air strikes.