A few days ago, I mentioned one of the baleful consequences of the U.S. pullout from Iraq: our current inability to stop the flow of arms from Iran to Syria via Iraqi airspace. This article highlights another worrying issue: the tensions between Arabs and Kurds. Two New York Times correspondents write:

When federal police agents sought to arrest a Kurdish man last month in the city of Tuz Khurmato in the Kurdish north of the country, a gunfight ensued with security men loyal to the Kurdish regional government.

Kurdish security forces, called the Peshmerga, have been in a standoff with the Iraqi Army near Kirkuk, a northern city claimed by Arabs and Kurds. When the bullets stopped flying, a civilian bystander was dead and at least eight others were wounded.

In response, the Iraqi prime minister, Nuri Kamal al-Maliki, rushed troop reinforcements to the area, and Masoud Barzani, the president of Iraq’s semiautonomous northern Kurdish region, dispatched his own soldiers, known as the Peshmerga, and the forces remain there in a tense standoff.

Prior to December 2011, such a dispute would have been mediated by U.S. troops positioned on both sides of the disputed Green Line dividing Kurdish territory from Iraq proper. American troops were even running joint patrols with the Iraqi army and the peshmerga in a confidence-building measure. But now the American buffer has been removed and tensions are predictably flaring.

Odds are that the Kurdish leader Massoud Barzani and Iraqi Prime Minister Nouri al-Maliki, wily survivors both, will step back from the brink. But you never know–they could miscalculate and, amid surging emotions on both sides, an actual war could break out. Certainly the odds of such a dangerous outcome have been appreciably increased by the White House’s irresponsible failure to secure an extension of the Status of Forces Agreement keeping U.S. troops in Iraq.