The Pentagon plan for a major ground assault to retake the northern Iraqi city of Mosul from Islamic State is bold, ambitious — and perplexing.
The Obama administration has set a goal of helping Iraq regain control of its territory and borders by the end of this year, and ousting the Sunni Muslim extremists from the country's second-largest city — one Islamic State calls a capital of its caliphate — would be a major objective.
And there is no question that a successful U.S.-backed assault with 20,000 to 25,000 Iraqi and Kurdish troops on a major urban center, should it occur, would mark a turning point in a shadowy war that has been largely limited to airstrikes and small skirmishes deep in the desert.
Whether the military blueprint is feasible is far from certain, however.
Under the outline disclosed Thursday to reporters, the assault could begin as early as April or May. Advisors with the U.S. Marines and Army Special Forces would help train and equip five Iraqi army brigades, each with about 2,000 troops, to serve as the main attack force. The brigades are to be drawn from battle-hardened units now on duty in Baghdad and elsewhere.
Iraqi counter-terrorism commandos would join the attack, while three brigades of Kurdish peshmerga fighters would try to seize approaches to the city from the north and west. Three Iraqi brigades would be held in reserve.
The U.S. military official who briefed reporters on condition of anonymity said Iraqi and Kurdish commanders "are absolutely committed to this." He said the goal is to launch the attack before the heat of summer and the start of Ramadan in mid-June.
But Mowaffak Rubaie, Iraq's former national security advisor and now a member of the parliament in Baghdad, seemed skeptical that Iraq will have sufficient capable troops so quickly.
"I believe this 'leak' is for diversional tactics and is not practical," Rubaie wrote in an email. "My estimate is Iraqi security forces would be probably ready by the end of this year or even early next year."
Tens of thousands of Iraqi troops abandoned their weapons and fled last year when far smaller forces of militants approached. Mosul fell with barely a fight in June, and only about 2,000 militants are believed to control the city.
Any attempt to retake the city now probably would require house-to-house fighting and U.S. air support, including airstrikes and intelligence, against an entrenched foe.
Even if the Pentagon decides to send U.S. special operations troops into the battle to help direct U.S. airstrikes, commanders are unlikely to approve bombing runs that could cause heavy civilian casualties. Iraqi troops thus would assume a greater burden of evicting the militants and securing the city.
The decision to share details and timing of the attack plan raised eyebrows in the Pentagon and on Capitol Hill. Critics said it was a political ploy by the administration to rebut charges that it has yet to score major gains against Islamic State.
In a letter to President Obama on Friday, Sen. John McCain (R-Ariz.), chairman of the Senate Armed Services Committee, and Sen. Lindsey Graham (R-S.C.) called the disclosure "deeply disturbing" and demanded to know who was responsible.
"Never in our memory can we recall an instance in which our military has knowingly briefed our own war plans to our enemies," they wrote. "These disclosures not only risk the success of our mission, but could also cost the lives of U.S., Iraqi, and coalition forces."
A Pentagon official defended the decision, however, saying the goal is to show the American public, allies in the region and Islamic State leadership that the U.S.-led coalition is gearing up to retake the militants' biggest battle prize.
"It sends a message to our allies that the Iraqis are finally getting serious about their country by taking this city," said the official, who was not authorized to speak publicly on the operation. "It also puts [Islamic State] in a defensive crouch, when they turn on CNN and see the cavalry is coming."
White House Press Secretary Josh Earnest said Iraqi ground forces must lead any attempt to oust Islamic State.
"This is an offensive that won't begin until the Iraqi security forces are ready," he said. "This is something that will be Iraqi-led and it will be carried out by Iraqi security forces," backed by coalition airstrikes.
For now, the conflict appears to be at a stalemate. The militants have not gained any major new objectives in recent months, but neither have they been forced out of any significant cities or towns in Syria or Iraq.
In the heaviest single battle of the war, Kurdish fighters backed by more than 700 coalition airstrikes broke a four-month Islamic State siege of the Syrian border town of Kobani last month. But most of the city, which had little strategic value, was left in rubble after the fighting.
Mosul is a far bigger trophy, and could involve a far more intense battle.
When it fell to Islamic State last summer, the militants captured vast stores of U.S.-supplied weapons, vehicles, ammunition and equipment.
Since then, according to Kurdish officials, the militants have reinforced their fighters, blocked access roads, dug defensive trenches around the city, and blown up a key bridge on the city's western edge.
They also have forged alliances with some former Iraqi military officers and local Sunni officials who supported autocrat Saddam Hussein before he was toppled after the 2003 U.S.-led invasion.
Still unclear is whether Kurdish fighters and Iraq's Shiite-dominated security forces would give their all to recapture a Sunni-dominated city.
"Mosul is not part of the Shiite or Kurdish core territories," said Christopher Harmer, a former Pentagon strategist now at the Institute for the Study of War, a nonpartisan public policy group in Washington. "Are these units really going to sacrifice thousands of lives to recapture a city, then give it to the Iraqi central government? I doubt it."
The U.S. official who briefed reporters conceded that the attack plan is still a work in progress.
"There are a lot of pieces that have to come together and we want to make sure the conditions are right," the official said. "But this is [the Iraqis'] plan. They are bought into it. They are moving forward."