Smoke rises above the Syrian city of Kobane after an airstrike by the U.S. led coalition, on Nov. 2. (Vadim Ghirda/AP)

Americans still don’t seem to get that the fight against the so-called Islamic State has just begun and will last for years.

They must also realize that U.S. military power won’t decide the issue.

“It’s a three- to four-year effort, because that’s what it’s going to take to get the indigenous forces prepared and to do this,” Gen. Ray Odierno, the U.S. Army’s chief of staff, told CNN on Wednesday.

“It’s just the beginning.” Defense Secretary Chuck Hagel said at a Thursday news conference. “This is a long-term effort.”

The next day, Rear Adm. John Kirby, Pentagon spokesman, told reporters, “You can’t judge the complete success of the campaign after . . . just three months [of U.S. and coalition forces bombing].”

“It’s going to take some time,” he added, repeating President Obama’s warning on Sept. 11, when he announced the Islamic State would be hit in Syria as well as in Iraq.

No matter. The message hasn’t registered.

The Defense Department is certainly preparing for a long fight.

For example, on Oct. 24 the Air Combat Command of the U.S. Air Force issued a notice to potential contractors that it plans a follow-on contract that could run for eight years, starting in October 2016, to operate, maintain and support Air Force Central Command’s major war reserve materiel facilities in Oman, Qatar, Kuwait and the United Arab Emirates.

DynCorp won the current contract in 2008. The new contract could go through 2024.

The sites hold prepositioned equipment for the U.S. Air Force and Army. Here’s just a few items:

●Mine-resistant ambush protected vehicles (MRAPs).

●Medical contingency hospitals for expeditionary medical support.

●Basic expeditionary airfield resources — facilities and equipment that could house 3,300 airmen and 72 fighter aircraft at expeditionary locations.

The contract proposal includes a section titled, “Munitions Contingency Operations at Al Udeid,” an air base in Qatar. It says that during “contingencies” the base will be a “munitions hub,” also utilizing facilities at “Falcon 78,” an ammunition storage area.

Another section of the proposal, “Employment in Time of War Plan,” requires the contractor to develop “a supplemental compensation and protection plan to retain a workforce capable of sustaining preparation and outload operations . . . in the event WRM [war reserve materiel] sites come under attack by hostile fire.”

The current contract runs upwards of $70 million a year, plus some additional costs.

That’s just for the Air Force.

The United States spent more than 4,000 U.S. lives and $800 billion in Iraq, fighting and trying over 11 years to rebuild that country after the ill-conceived 2003 invasion.

For almost eight of those years, we had more than 70,000 U.S. troops there. The effort did not result in a Baghdad government that had the support of the nation’s ethnic and religious elements.

Americans should have learned from that experience. And from Vietnam 40 years ago.

Obama has.

Iraqi boots on the ground are the only ones that can defeat the Islamic State in Iraq. But that also requires a political settlement among Shiite, Sunni, Kurd and other ethnic and religious groups that make up what is an artificial nation assembled decades ago by Western European governments.

Obama must remain firm in keeping U.S. military advisers in Iraq at division or brigade headquarters and not at lower tactical levels, where they could be directing small-unit operations, for example.

That was the slippery slope in Vietnam, then Iraq and Afghanistan. If Iraqi forces aided by U.S. advisers don’t turn the tide, it would be a long-term mistake to send in U.S. combat troops. The result would be permanent U.S. occupation — or leaving, as we did in December 2011.

So far, Obama has leveraged limited military support to try to jumpstart a tone of governmental inclusion.

Obama delayed instituting U.S. bombing of Islamic State units until the Baghdad leadership changed, with former prime minister Nouri al-Maliki giving way to Prime Minister Haider al-Abadi.

Now the United States may be delaying the dispatch of U.S. assist-and-advise teams to headquarters in the Anbar area that’s threatened by Islamic State forces until, as Kirby put it, there is “increased collaboration between Iraqi security forces and Sunni tribesmen” in that area.

The U.S. long-term plan calls for the reestablishment of an Iraqi national guard system as a way to bring Sunni, Shiite, Kurd and local militias into the Iraq security system, leaving the mostly-Shiite Iraqi army to protect the borders.

However, as Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, said Thursday, that step requires the Iraqi government to pass a law to establish the guard system, and that will push implementation to next year.

Odierno summed it up this way: “The long-term war against [the Islamic State] needs to be fought by the indigenous capability there. It needs to be fought by Iraqis. It needs to be fought by Syrians. It needs to be fought by other Arabs, because it’s their country and they need to win that back.”

He’s right, and Americans must understand and accept our limitations in this fight.

For previous Fine Print columns, go to washingtonpost.com/fedpage.