Take it from a man who knows: The Iraqi army’s first big attempt to roll back the Islamic State is going to be a violent mess. 
Several months after thousands of American advisers showed up for training sessions, Iraqi troops still aren't ready for combat. Iranian-backed Shiite militias will do most of the fighting against the Islamic State (ISIS) militants in Tikrit and other largely Sunni towns and cities in Iraq, raising the chances of more sectarian slaughter. And even if the militias do manage to drive out ISIS, Baghdad doesn't have a viable plan to rebuild what’s likely to be a region reduced to rubble.
That's the grim assessment of a retired U.S. Army lieutenant general, James Dubik, who oversaw the training of Iraqi soldiers in the final months of the eight-year U.S. occupation. Those troops fled when ISIS showed up last summer, stripping off their uniforms and abandoning millions of dollars' worth of American weapons. 
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“Yup,” Dubik says with a dry chuckle, “those were my guys.”
The general, like other military experts, was watching closely last week as some 30,000 Iraqi troops launched a counter-offensive against ISIS in Tikrit, the hometown of Saddam Hussein. The attack is the first phase of a larger campaign to recapture Mosul, the country’s second-largest city and the de facto ISIS capital in Iraq. 
For the past six months, U.S. special forces advisers have been training several Iraqi brigades for the battle. At first, U.S. military officials said the push would start as soon as April. Later, they backpedaled, saying they would leave it to the Iraqis to announce when the counter-offensive will begin. Dubik hopes they don't act prematurely. "The limits on their capacity and their logistics will force a culmination before the Mosul operation is complete," he tells Newsweek.
Trying to recapture Tikrit first makes sense, according to Dubik. "It’s a preparatory phase for the Mosul operation," he says. "Let’s see how the enemy defends. Let’s see how we do against them. Let’s see how our resupply and replacement systems work. If we’re successful, we’ll shorten the supply line between Baghdad and Mosul. We’ll also have a much closer jumping-off point for going to Mosul."
It’s what comes next that really worries the general, who received a Ph.D. in philosophy from Johns Hopkins and spent a year as a Catholic monk before joining the Army in 1975. In the unlikely event that the Iraqi troops take Tikrit and then Mosul, someone will still have to remain in control of the latter’s one million residents. Right now, that job will go to a brigade of roughly 5,000 Sunni policemen who escaped from Mosul and are now being trained in Kurdistan. 
Dubik is skeptical of that aspect of the plan. “I'm doubtful that's going to be sufficient,” he says. “That approach has not worked to date. It's been tried a number of times in Iraq,” including when 100,000 U.S. troops, American airpower and an extensive intelligence network were there to support the Iraqis. “The police were inadequately trained and equipped,” he adds. “Same approach was tried in Afghanistan, where it failed miserably.”
First, of course, the Iraqis have to win the battle of Tikrit. Since last summer, they’ve tried and failed to recapture the city several times. Now, with Iraqi forces massing for another assault, ISIS defenders in Tikrit have erected formidable defenses, including tall concrete barriers placed at various entry points along with booby traps, car bombs and mortar and artillery positions to make it difficult to advance. "Tikrit is one big IED," says Jessica Lewis McFate, a former Army intelligence officer in Iraq and Afghanistan. She and others say there's no reliable intelligence about how many ISIS fighters are in the city.
The poor track record of Iraq's military forces has prompted several Iranian-supported Shiite militias to volunteer to dislodge the ISIS militants from Tikrit and Mosul. Accompanying them: a number of Iranian military advisers, including General Qassem Suleimani, commander of the the Revolutionary Guard Corps' elite Quds Force. He’s a hated figure within the U.S. military, which suffered substantial casualties from Shiite militia attacks directed by Suleimani during the U.S. occupation. 
Iranian involvement has created an awkward situation for the Obama administration, which has been launching air strikes against ISIS in Iraq and Syria since last August, effectively putting Washington and Tehran on the same side. Administration officials insist they don't coordinate air strikes with Tehran, but they acknowledge they consult with Iraqi commanders, who then make sure U.S. actions don’t conflict with those of the Iranians and the Shiite militias.
Iranian-backed Shiite militias like the Badr Brigade and K’taib Hezbullah say their fighters make up two-thirds of the 30,000-strong force that’s gathered near Tikiti. These Shiite fighters have been waiting for a battle with ISIS, which has called Shiites apostates and said they should be slaughtered. But the presence of Shiite fighters on a predominantly Sunni battlefield is cause for concern, says Dubik and other military analysts. 
After U.S. troops withdrew from Iraq, they note, Shiite militias were involved in several instances in which atrocities were committed against Iraqi Sunnis. The government of Iraqi prime minister Haider al Abadi is investigating the latest incident, in which pro-government Shiite militiamen allegedly massacred 70 Sunnis in January when they drove ISIS fighters out of an area northeast of Baghdad. 
"The real question is can you convince the Shiite militias not to do widescale ethnic cleansing in the fight against ISIS and then leave after Mosul is taken," said Michael O'Hanlon, a military analyst at the Brookings Institution. "I'm a little worried about that part. I'm not persuaded we can expect the Shiite militias to liberate Mosul and then leave."
Another element of the Iraqi counter-offensive that remains unclear: The role of the Kurdish peshmerga. Since ISIS swept into northern Iraq last summer, the well-trained and capably led Kurdish forces have blunted the group's advance into the Kurds' autonomous region and even recaptured some ISIS-held territory outside of their enclave. But any fight for Mosul will probably require bloody, house-to-house urban warfare, so Kurdish commanders are not keen on helping to take back the predominantly Sunni city. As a result, Kurdish officials have spoken of contributing a peshmerga force to block the areas to the north and west of Mosul to prevent ISIS supplies and reinforcements from reaching the city. 
If Tikrit proves difficult to recapture, Dubik and other military analysts predict any battle to retake Mosul will be far more complex, even with U.S. air support. Baghdad must assume that ISIS will stage diversionary attacks in other parts of country to draw Iraqi forces away from the counter-offensive. In 2004, when the U.S. battled Al-Qaeda militants for control of Fallujah, a much smaller town in Iraq's Anbar province, it needed two brigades of highly trained Marines and nearly two months to secure the town. "Fallujah would be just one neighborhood in Mosul," says McFate. Unless ISIS fighters abandon the city, she predicts any battle will leave it in ruins.
Dubik is equally pessimistic. "This is D-Day,” he says, comparing the advance on Tikrit to the Allied invasion of France in June 1944. “What happens afterward? How does this fit into an overall operational campaign to re-establish the sovereign borders of Iraq and re-establish political sovereignty within those borders? I haven't heard boo about that aspect of the plan."