Turkey in Iraq? Don't even go there.

As if Iraq were not complex enough, now Turkey's troops are massed along the rugged border between the two countries. The Turks threaten an incursion to root out separatist Kurds who attack inside Turkey. If those involved can lift their view to the height of the mountains in this region, a dangerous escalation could be avoided.

At the moment, foothill-thinking prevails. The Turkish military, which seems to be gunning for a major incursion, appears to be less concerned about upsetting the only relatively stable portion of Iraq, and more focused on the immediate task of stopping deadly attacks by the Kurdistan Workers Party, or PKK, which the US and European Union designate as terrorists. The powerful military also hopes its tough posture can influence Turkey's elections next month.

Meanwhile, the regional leadership of Kurdish northern Iraq, in whose power it is to hand over PKK organizers to Turkey, seems satisfied to let this problem fester, out of local sympathy for the PKK. Since being divvied up at the end of World War I, many Kurds in Iraq and neighboring countries yearn to unite in their own state.

The northern Iraqi leaders apparently want to use their influence with the PKK as a bargaining chip to force Turkey's acceptance of Kurdish control over the oil-rich Iraqi city of Kirkuk (to be determined in a December referendum). Such control could encourage Kurdish independence. Turkey shudders at the thought of a Kurdistan that might some day absorb Turkey's substantial Kurdish minority.

The United States, meanwhile, is preoccupied with immediate, and consequential, worries In Iraq. It has its hands full with the military surge, and relies on troop support from Iraq's Kurdish peshmerga forces. Antagonizing the Iraqi Kurds could upset a delicate security arrangement.

All parties here need to see the bigger picture. A major incursion on the part of Turkey could further destabilize Iraq, and possibly invite military intervention from Iran. It could also severely damage, if not end, Turkey's chance to join the European Union.

Should a serious incursion occur, the US would be in the tough position of deciding whether to side with Turkey, its longtime, strategic NATO ally, or its more recent tactical friends, the Iraqi Kurds. It's unwise to further alienate Turkey, where public approval of Washington has plummeted. Precisely because it is allied with Turkey and the Iraqi Kurds, the US, more than anyone, is in a position to bring these two together and solve the PKK problem.

Iraqi Kurds, meanwhile, might consider this question: Would they rather have Turkey as a friend or an enemy? The shelves of northern Iraq are full of Turkish products. Its roads carry fuel trucks from Turkish refineries. Turkish companies are building its infrastructure.

Turkey can, and hopefully will, show restraint. In the 1980s and 1990s, it warred with its Kurdish minority and more than 30,000 people were killed. After the Kurdish rebel leader was arrested, a truce ensued and Turkey made great strides in granting Kurds language and local governance rights.

But the PKK has resumed its old ways, and must be stopped. Best for the Iraqi Kurds, with US encouragement, to tackle this threat now.