Turkish troops have launched what is possibly the largest Turkish ground incursion into Iraq since the toppling of the Saddam Hussein regime in 2003. The Turkish media reports that 3,000 to 10,000 troops crossed the Iraqi border on Friday in pursuit of separatist insurgents from the Kurdistan Workers’ Party (pkk). According to the Associated Press:

It’s the first confirmed ground operation by the Turkish military into Iraq since the U.S.-led invasion that toppled Saddam Hussein, and it raised concerns that it could trigger a wider conflict with the U.S.-backed Iraqi Kurds.The ground operation started after Turkish warplanes and artillery bombed suspected rebel targets on Thursday, the military said on its website. The ground incursion was backed by the Air Force, the statement said.Turkey has conducted air raids against the pkk guerrillas in northern Iraq since December, with the help of U.S. intelligence, and it has periodically carried out so-called “hot pursuits” in which small units sometimes spend only a few hours inside Iraq.So the announcement of a cross-border, ground incursion of a type that Turkey carried out before the U.S.-led invasion of Iraq in 2003 was a major development in the conflict.

Although this Turkish incursion is only meant to root out pkk guerrillas hiding in northern Iraq, the fear is that a Turkish invasion could trigger conflict with Kurds throughout the region. A large-scale guerrilla-style conflict in northern Iraq would destabilize what is now the most stable region in Iraq. Southern Iraq is already embroiled in Shiite-Sunni conflicts. A Turkish-Kurdish conflict is the north would only further highlight America’s failure to bring peace to the region.

America cannot back the Kurds for fear of alienating the Turks, who have been among their few friends in the Middle East. Yet they cannot back the Turks for fear of further escalating Iraqi tensions. As American leadership increasingly talks about withdrawing the troops from Iraq, watch for Iran to move in and stabilize the situation. America’s half-hearted efforts in Iraq are playing right into Iranian hands.

For more information on the future of Iraq, read “Washington’s Kurdish Quandary” and “Is Iraq About to Fall to Iran?”