Last, but not least, with no overarching oil law and the status of the oil-rich city of Kirkuk still up in the air, relations between Arabs and Kurds are worsening. Indeed, the dispute over rule of Kirkuk is the main reason the crucial provincial elections law recently crashed and burned in the Iraqi Parliament. Simmering tensions between Arabs, Kurds, and Turkomen are already bubbling over into ethnic clashes. Thousands of Kurds protested in Kirkuk over the July version of the elections law, which narrowly passed over Kurdish objections before being vetoed by Iraq’s president, a Kurd. When a suicide bomber attacked the crowd, a mob of Kurds responded by attacking the nearby headquarters of the Turkomen political front, and Turkomen guards then fired on the crowd. All told, the day’s violence left 28 people dead and more than 200 wounded.

The same fault line plagues the northwestern province of Ninawa, home to Mosul and the largest remaining contingent of AQI fighters. Sunni Arabs are the majority in Ninawa, but Kurds control a disproportionate amount of power in the provincial council and security forces. Remnants of AQI have seized on this division and managed to carve out a sanctuary. Unlike many other Sunni-dominated areas, Sunni Arabs in Mosul have not turned en masse against AQI because insurgents have wisely focused most of their attacks on Kurdish security forces rather than Sunni civilians. This positions AQI as defenders of the Sunni Arab population against Kurdish expansion, making it difficult to eliminate the last AQI safe haven.

In short, Iraq could easily backslide into mass violence. The surge was supposed to be about buying time to build Iraqi capacity and create breathing space for political accommodation. Yet, as Iraqi capacity and confidence have increased, Maliki and his allies seem less inclined to reach out to their adversaries. By emphasizing capacity over political will, the Bush administration has failed to force Iraqi leaders to make tough compromises. Instead, it too often conveys messages of unconditional support to the Iraqi government that undermine the behind-the-scenes cajoling of U.S. commanders and diplomats.

This flawed political strategy must change. Whether the next president is named McCain or Obama, he must make it crystal clear to Iraqi leaders that the era of unconditional support is over: Make political progress or risk losing American backing. Despite their increasingly boastful rhetoric and demands for a U.S. departure, most Iraqi leaders know they will need continued security, technical, and diplomatic assistance for years to come, even as American forces draw down. That gives the next commander in chief leverage he can use from day one. The United States will never be able to truly cash in on the surge until it cancels its blank checks to the Iraqi government.