If the United States was looking for the surest way to lose Iraq War 3.0, it might start by retraining the failed Iraqi Army to send north — alongside ruthless Shi’ite militias — into Sunni-majority territory and hope that the Sunnis will welcome them with open arms, throwing out the evil Islamic State.

Maybe it’s time for a better plan.

And the way to find one is by understanding how we lost Iraq War 2.0. We need a plan to create a stable, tri-state solution to the Sunni-Shi’ite-Kurd divide, or the current war will fail as surely as the previous one.

A critical first step is, of course, to remove Islamic State from the equation, but not how the Obama administration envisions. The way to drive Islamic State out of Iraq is to remove the reason Islamic State has been able to remain in Iraq: as a protector of the Sunnis. In Iraq War 2.0, the Iraqi Sunnis never melded politically with al Qaeda; they allied out of expediency, against the Shi’ite militias and the Shi’ite central government. The same situation applies to Islamic State, the new al Qaeda in Iraq.

The United States is acting nearly 180 degrees counter to this strategy, enabling Shi’ite militia and Iranian forces’ entry into Anbar and other Sunni-majority areas to fight Islamic State. The more Shi’ite influence, the more Sunnis feel they need Islamic State muscle. More Iranian fighters also solidify Iran’s grip on the Shi’ite government in Baghdad, and weakens America’s. The presence of additional Sunni players, like the Gulf States, will simply grow the violence indecisively, with the various local factions manipulated as armed proxies.

Iraq in 2007 was, on the surface, a struggle between insurgents and the United States. However, the real fight was happening in parallel, as the minority Sunnis sought a place in the new Shi’ite-dominated Iraq. The solution was supposedly the Anbar Awakening. Indigenous Iraqi Sunnis would be pried lose from al Qaeda under American protection (that word again), along with the brokered promise that the Shi’ites would grant them a substantive role in governance. The Shi’ites balked almost from day one, and the deal fell apart even before America’s 2011 withdrawal — I was in Iraq with the Department of State and saw it myself. The myth that “we won” only to have the victory thrown away by the Iraqis — a favorite among 2.0 apologists — is very dangerous. It suggests repeating the strategy will result in something other than repeating the results. The Sunnis won’t be so easily fooled again.

Progress otherwise in Iraq? The new prime minister has accomplished little toward unity, selecting a Badr militia politician to head the Interior Ministry, for example. The Badr group has been a key player in sectarian violence.

Islamic State still controls 80 percent of Anbar Province, the key city of Mosul and is attacking in Ramadi. U.S. air strikes cannot seize ground. The Iraqi Army will never rise to the fullness of the challenge. One can only imagine the thoughts of the American trainers, retraining some of the same Iraqi troops from War 2.0.

Elsewhere, the Kurds are already a de facto separate state. Their ownership of Arbil, the new agreement to allow the overt export of some of their own oil, and the spread of the peshmerga to link up with Kurdish forces in Syria, are genies that won’t go back into the bottle. America need only restrain Kurdish ambitions to ensure stability.

Present Iraq strategy delays, at great cost — in every definition of that word — the necessary long-term tristate solution. It is time to hasten it. The United States must use its influence with the Shi’ites to have their forces, along with the Iranians, withdraw to Baghdad. America would create a buffer zone, encompassing the strategically critical international airport as a “peacekeeping base.” Using air power, America would seal the Iraq-Syria border in western Anbar, at least against any medium-to-large scale Islamic State resupply effort. Arm the Sunni tribes if they will push Islamic State out of their towns. Support goes to those tribes who hold territory, a measurable, ground-truth based policy, not an ideological one. Implementing the plan in northwest Iraq can also succeed, but will be complicated by Kurd ambitions, greater ethnic diversity among the Iraqis and a stronger Islamic State tactical hold on cities like Mosul. There’ll be another tough challenge, the sharing of oil revenues between the new Sunni and Shi’ite states, so this plan is by no means a slam-dunk.

The broad outline is not new; in 2006 then-Senator Joe Biden proposed a federal partition of Iraq along the Bosnian model. Bush-era zeal kept the idea from getting a full review. But much has transpired since 2006.

If the tristate plan works, it will deny Islamic State sanctuary where it is now most powerful, and a strategy for northwest Iraq may emerge. America will realize its long-sought enduring bases in Iraq as a check on Iranian ambitions and an assurance of security for the embassy. The president can decouple Syrian policy from Iraq. An indefinite American presence in Iraq will not be fully welcomed, though one hastens to add it basically is evolving anyway.

For advocates of disengagement, this is bitter medicine. But we are where we are in Iraq, and wishful thinking, on their part or the White House’s, is no longer practical. A divided Iraq, maintained by an American presence, is the only hope for long-term stability. Otherwise, stay tuned for Iraq War 4.0.

TOP PHOTO: Iraqi security forces march on the outskirts of Najaf, south of Baghdad Nov. 19, 2014. REUTERS/Alaa Al-Marjani

INSET PHOTO: A tank belonging to the Kurdish security forces is seen being transported during an intensive security deployment in Diyala province north of Baghdad Nov. 19, 2014. REUTERS/Stringer