In 2006, Vice President Joe Biden co-authored a New York Times op-ed in which he suggested that the only way to create a stable environment in Iraq was to partition the country along ethnic and religious lines. The authors’ hope was to integrate these semi-autonomous zones into a federal system that would preserve the fragile Iraqi peace once maintained by force. A newly Democratic U.S. Senate enthusiastically endorsed that plan in 2007, but it fell out of favor in the wake of the successful “surge” strategy.

That idea seems to making a comeback, however, as Iraq descends into chaos as the insurgent Islamist group ISIS continues its advance.

Speaking to MSNBC host Andrea Mitchell on Monday, Washington Post columnist David Ignatius said that the ISIS had “effectively partitioned” Iraq.

One of the co-authors of the famous Biden op-ed, president emeritus of the Council on Foreign Relations, Leslie Gelb, is less than sanguine about the prospects of a truly divided Iraq. Speaking to Washington Post reporters over the weekend, Gelb said that a true partitioning of the country would create three new states, none of which are economically viable on their own.

“This is the worst of all possible worlds – anarchy!” he told the Post. He is not alone.

Reidar Visser, a historian of Iraq educated at the University of Oxford who is based at the Norwegian Institute of International Affairs, has been a vocal critic of the way that the United States has stressed proportional sectarian representation rather than national Iraqi unity. He sees the current situation as disastrous, and worries that it may widen. “A formal partition of Iraq would add fuel to the flames of Syria and potentially could intensify current sectarian strife in places like Lebanon and Saudi Arabia,” he writes in an e-mail.

But the division of Iraq is becoming a de facto reality.

Observing that Iraq has devolved into two warring ethno-religious states and a third, relatively stable Kurdistan in the North, the columnist David Frum asked if the U.S. was best served by abandoning the effort to mediate that conflict and focus on securing its vital interests:

Q: is it not now the US interest in Iraq that the Kurds end up controlling as much as possible of the failing nation’s oil reserves?

— David Frum (@davidfrum) June 16, 2014

To which Ed Morrissey replied with another question: maybe it’s not merely in American interests but the West’s interests, both in economic and security terms, to treat Iraq as three distinct states:

@davidfrum Better Q: Is it now in Turkey's interest to strengthen the Kurds as a buffer between themselves and ISIS?

— Ed Morrissey (@EdMorrissey) June 16, 2014

While a divided Iraq, even in a federalist structure, was not the preferred method for maintaining peace in Iraq, it may be the only remaining viable option. An international peacekeeping force of the scale necessary to enforce a cease fire between sectarian groups is simply not forthcoming.

While diplomats around the world debate the future of Iraq, observers are beginning to notice that the country has been “effectively partitioned” for some time.