Editor’s Note: This report is based on interviews with U.S. military engineers and others before and during the writer’s two weeks as an embedded reporter at major U.S. bases in Iraq.

BALAD AIR BASE, Iraq – The concrete goes on forever, vanishing into the noonday glare, 2 million cubic feet of it, a mile-long slab that’s now the home of up to 120 U.S. helicopters, a “heli-park” as good as any back in the United States.

At another giant base, al-Asad in Iraq’s western desert, the 17,000 troops and workers come and go in a kind of bustling American town, with a Burger King, Pizza Hut and a car dealership, stop signs, traffic regulations and young bikers clogging the roads.

At a third hub down south, Tallil, they’re planning a new mess hall, one that will seat 6,000 hungry airmen and soldiers for chow.

Are the Americans here to stay? Air Force mechanic Josh Remy is sure of it as he looks around Balad.

“I think we’ll be here forever,” the 19-year-old airman from Wilkes-Barre, Pa., told a visitor to his base.

The Iraqi people suspect the same. Strong majorities tell pollsters they’d like to see a timetable for U.S. troops to leave, but believe Washington plans to keep military bases in their country.

The question of America’s future in Iraq looms larger as the U.S. military enters the fourth year of its war here, waged first to oust President Saddam Hussein, and now to crush an Iraqi insurgency.

Ibrahim al-Jaafari, interim prime minister, has said he opposes permanent foreign bases. A wide range of American opinion is against them as well.

Such bases would be a “stupid” provocation, says Gen. Anthony Zinni, former U.S. Mideast commander and a critic of the original U.S. invasion.

Events in explosive situations like Iraq’s, however can turn “no” into “maybe” and even “yes.”

The Shiite Muslims, ascendant in Baghdad, might decide they need long-term U.S. protection against insurgent Sunni Muslims. Washington might take the political risks to gain a strategic edge – in its confrontation with next-door Iran, for example.

The U.S. ambassador to Iraq, Zalmay Khalilzad, and other U.S. officials disavow any desire for permanent bases. But long-term access, as at other U.S. bases abroad, is different from “permanent,” and the official U.S. position is carefully worded.