At the center of President Obama’s strategy for defeating the Islamic State is an empty space, argues The Post's David Ignatius, and unless this gap is filled, Obama’s plan won’t work. (Tom LeGro/The Washington Post)

At the center of President Obama’s strategy for dealing with the Islamic State is an empty space. It’s supposed be filled by a “Sunni ground force,” but after more than a year of effort, it’s still not there. Unless this gap is filled, Obama’s plan won’t work.

Otherwise, Obama made a reasonable case in his speech to the nation Sunday night. He’s right to argue for patience and persistence in fighting the Muslim terrorists, rather than “tough talk.” He’s correct that the United States shouldn’t feed the jihadists’ fantasies with “a long and costly ground war.” And he’s especially right that we’ll be safer at home and abroad if most Muslims are allies against the extremists.

But there was a mysterious black box in the middle of Obama’s speech. Here’s how he tried to explain it: “The strategy that we are using now — airstrikes, special forces and working with local forces who are fighting to regain control of their own country — that is how we’ll achieve a more sustainable victory.”

What “local forces” is Obama talking about? If he means Kurdish fighters in Iraq and Syria, yes, they’ve performed admirably. In Kurdish areas. They don’t want to clear and hold the Sunni heartland of the Islamic State, nor should they. If Obama is talking about the Shiite-led Iraqi military, its performance is still just barely adequate, even backed by U.S. air power, and it is disdained and mistrusted by the Sunnis of Ramadi, Fallujah and Mosul. If he’s talking about the Islamist brigades in Syria armed by Saudi Arabia, Turkey and Qatar, it’s still not entirely clear whether they’re friend or foe.

The disturbing fact is that a strong, reliable, indigenous Sunni ground force doesn’t exist yet in Iraq or Syria. The United States has been trying to fix this problem since the fall of Mosul in June 2014, with very little success. We’re like the joke about the starving economist who needs to open a can of beans on a desert island and posits: “Assume we had a can opener!”

President Obama addressed the attacks in San Bernardino, Calif., and laid out his plan to destroy the Islamic State during his address from the Oval Office. (Associated Press)

Consider the false hopes and missed connections over the past year: In Iraq, U.S. trainers were dispatched to Al Asad and Al Taqaddum air bases in Anbar province to train thousands of Sunni tribal fighters. The tribesmen mostly didn’t show up, and no wonder: The Shiite-led government in Baghdad still refuses to approve a Sunni “national guard” with real power. In Syria, Congress authorized a $500 million plan to train and equip a largely Sunni force to fight the Islamic State. Only a few hundred signed up, instead of the expected 5,000, and the first wave of fighters walked into a trap and was savaged by jihadists in northern Syria.

Why have these efforts gone so badly, and what needs to be fixed? Basically, I’d argue that Sunnis don’t trust an America that turned their world upside down in the 2003 invasion that toppled Saddam Hussein. Tribal leaders have been our default Sunni strategy ever since: We’re trying now to use them as mercenaries against the Islamic State. But it’s a corrupt bargain on both sides.

The Sunni no-show problem illustrates a deeper trauma. Across the Middle East, Sunnis are experiencing a kind of vertigo. The Sunni powerhouses — Egypt, Syria, Iraq, Libya — are in ruins. The people feel dispossessed and disillusioned, disgusted with the autocrats who ruled them before and the religious fanatics who want to rule them today.

Filling this Sunni vacuum with new self-confidence will be the work of a generation, but it must start now, for it’s an essential part of defeating the jihadists. The West’s best think tanks should be working on this problem; the Arab world’s brightest young activists should be making plans for governance and economic development. Global institutions such as the United Nations, the World Bank and the International Monetary Fund should be developing plans for trusteeship, reconstruction and governance.

It’s 1944 in the Arab world: Defeating the jihadists demands the creation of a healthy Sunni body politic.

What would a revived Sunni heartland in Iraq and Syria look like? Well, you can get a pretty good idea by examining Iraqi Kurdistan. It flowered under a U.S. no-fly zone known as Operation Provide Comfort that started in 1991. Under this protective cover, investment, security and political stability came together in a virtuous cycle.

When we think about the future of Iraq and Syria, we should have in mind vibrant Sunni provinces that, like Kurdistan, are part of a loose federal state. In building a strategy for defeating the Islamic State, creating this “Sunnistan” will be the long pole in the tent.

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