Our editorial: After Mosul, then what?

The Iraqi army and Kurdish fighters, aided by American forces, are moving steadily toward the ISIS stronghold of Mosul. Within weeks, this keystone city of the Islamic State likely will be liberated and back under Iraq’s control.

That’s not to suggest ISIS will leave Mosul easily. The city is too important to its ambitions for an Islamic caliphate and is considered its cultural center. ISIS will make its foes take back the city inch by inch in what is expected to be a bloody fight that will use the 1 million remaining residents as human shields.

But the 30,000 forces aligned against ISIS should have the firepower to prevail.

And then what?

Mosul is the last stand for ISIS in Iraq. It has already been driven out of most other key cities, including Tikrit and Ramadi.

After Mosul, there is only the desert for ISIS. And its leaders vow to go there to regroup and continue to plot and launch insurgent attacks. That’s the strategy ISIS pursued after it was driven out of Iraqi cities in 2007 by the U.S. troop surge.

For years it tormented Iraq from its desert hideaways, exploited the nation’s leadership void to foment dissent and recruit supporters and came storming back in 2013.

Both Iraq and the United States must be aware that the fight against ISIS doesn’t end with a Mosul victory.

ISIS will be hard to chase in the desert, where it is already returning to remote areas that were previously liberated, recruiting fighters and launching guerrilla attacks.

The U.S. must continue to help Iraq keep ISIS at bay. It must also help dislodge it from Syria, drive it out of the Persian Gulf region and counter its growing influence in Egypt, Pakistan, Afghanistan and elsewhere.

This remains a long-term war. ISIS has proven in the past its ability to knit together small cells into a deadly force. If it’s left alone anywhere, nowhere is safe.

The two presidential candidates mostly dodged the question of ISIS in Iraq in the last debate. Hillary Clinton generally supports the current Obama administration plan of providing mostly air support for Iraqi and Kurdish fighters. Donald Trump, who blames the rise of ISIS on Obama/Clinton neglect, says he will engage the Russians in defeating the terrorist group.

As for Iraq itself, it must follow battlefield victory with political unity.

Iraq today is even more fragmented than it was three years ago. With ISIS gone, Iraqi Sunnis must be brought into the fabric of the country’s political and social life, and not subjected to brutal reprisals by the Shia majority.

The U.S. is reluctant to engage in nation building, as it should be. And the Iraqi people have made it clear it does not want American troops to serve as a police force to keep its sparring factions apart. But it must find ways to help Iraq with the difficult diplomatic challenge it faces in becoming one people.

It is encouraging that the Kurdistan Region’s Peshmerga is fighting alongside regular Iraqi troops. The Kurds, too, must be included in the government in Baghdad if Iraq is to hold together.

ISIS rose out of Iraq’s political dysfunction. Unless it can find a path toward a functioning government that embraces all its factions, ISIS will be waiting in the desert for yet another bloody return.