This was true even of the most ambitious (and foolhardy) architects of the Iraq invasion, who intended to upset a dictator-dominated status quo … but not, they mostly thought, in a way that would redraw national boundaries. Instead, the emphasis was on Iraq’s potential for post-Saddam cohesion, its prospects as a multiethnic model for democratization and development. That emphasis endured through the darkest days of our occupation, when the voices calling for partition — including the current vice president, Joe Biden — were passed over and unity remained America’s strategic goal.

But now that strategy has almost failed. De facto, with the shocking advance of militants toward Baghdad, there are now three states in what we call Iraq: one Kurdish, one Shiite and one Sunni — with the last straddling the Iraq-Syria border and “governed” by jihadists.

This means that Iraq is now part of an arc, extending from Hezbollah’s fiefdom in Lebanon through war-torn Syria, in which official national borders are notional at best. And while full dissolution is not yet upon us, the facts on the ground in Iraq look more and more like Peters’s map than the country that so many Americans died to stabilize and secure.