By Mark Thompson / Washington
February 11, 2016

Like a video playing out in fast motion, the 1,000-ft. bridge surged across the Warrar canal just before Christmas. Huge trucks dumped aluminum ramps, midsections and high-powered, flat-bottomed minitugs on one bank, just outside Ramadi, the capital of Iraq’s western Anbar province. The city had been seized by ISIS seven months earlier, and now the Iraqi government wanted it back. Without an American soldier in sight (or any noteworthy enemy fire, for that matter), 400 Iraqi troops protected the 60 Iraqi bridge builders from ISIS attack as drones patrolled overhead, sending video images back to Baghdad.

Within hours, engineers from the 15th Iraqi army division had completed the $10 million, 100-ton floating bridge–and 80 miles east, in Baghdad, U.S. military officers cheered. The Iraqi forces had been trained by members of the U.S. Army’s 814th Engineer Company, which built bridges at Normandy during World War II. The Americans celebrated as 1,500 elite Iraqi troops and 300 vehicles trundled across the new bridge and began the fight to retake the city. Their victory on Dec. 22 marked a high point in the war on ISIS. “I’m biased, because I’m an engineer, but it’s really one of the bright and shining lights of what we’ve done here,” says Major Justin Pritchard of the 82nd Airborne Division. “It demonstrated the capability of the Iraqis to project combat power.”

The good news is that the Iraqi military–which has been a huge disappointment, despite a $25 billion U.S. investment–proved capable of building the bridge that helped take back Ramadi. The bad news is that the U.S. had sent the bridge to Iraq last year to retake Mosul, Iraq’s second largest city, which ISIS seized in June 2014–and which it still holds. When a lack of Iraqi ground forces postponed U.S. hopes of retaking Mosul last spring, the bridge was used in Ramadi instead. That detour is the war against ISIS in a nutshell: two steps forward, one step back.

The U.S. has been carrying out a slow but steady military campaign against ISIS in Iraq and Syria, one that Washington hopes will keep the terrorist group too busy to plot more attacks like the one in Paris last fall that killed 130 people. But ISIS is “determined to strike the U.S. homeland,” James Clapper, the Director of National Intelligence, told Congress on Feb. 9, warning that such prospects “remain a critical factor in our threat assessments for 2016.” Yet despite that danger, the 20 bombing missions a day that the U.S.-led coalition has carried out on average against ISIS since August 2014 works out to just one-eighth the rate of U.S. strikes on the Taliban in 2001. “They say their goal is to destroy ISIS, yet they have this very slow attrition strategy,” says Anthony Zinni, a retired four-star Marine general. “It’s a flawed and high-risk strategy without a strategic end state that makes sense.”

Recently Defense Secretary Ashton Carter has begun making hawkish noise. “This is a fight of civilization for its own survival,” Carter said on Feb. 2, declaring that he needs $7.5 billion to fight ISIS next year–a 50% boost from current spending levels. “We’re going to do more, because we have got to win.” But President Obama continues to refuse to dispatch large numbers of U.S. troops to Syria or Iraq, and few experts believe that a strategy that Anthony Cordesman of the Center for Strategic and International Studies dismisses as “creeping incrementalism” will be enough to dislodge ISIS from its self-proclaimed caliphate–especially when other players in the region, like Russia, are doing more. “ISIS is already an enduring feature of the Middle Eastern landscape,” says Emile Hokayem, a Middle East expert at the International Institute for Strategic Studies’ Bahrain office.

There’s no doubt that ISIS has suffered real reversals on the battlefield. Pentagon officials say ISIS’s territory in Iraq and Syria peaked in May 2015. Since then, they estimate, ISIS has lost about 40% of its Iraq holdings and 10% of the land it held in Syria. Instead of seizing new territory, ISIS fighters are digging tunnels and knocking holes in adjoining houses to elude detection. Allied attacks on ISIS oil wells and banks have forced the group to cut its fighters’ biweekly paychecks in half. Forced conscription and executions of deserters are on the rise.

Yet even while ISIS loses territory, it boasts a renewable supply of fighters. In late 2014, the U.S. estimated that there were as many as 31,500 ISIS soldiers. Pentagon officials have privately said 20,000 ISIS fighters have been killed since. Yet on Feb. 4, the White House said the number of ISIS fighters in Iraq and Syria could still be as high as 25,000. That suggests the bombing is ineffective, U.S. intelligence is lousy or those killed have been replaced, perhaps by foreign fighters. Most likely, the truth is some combination of all three. It reminds Zinni of an earlier American conflict: “We won every battle in Vietnam but lost the war.”

Even as ISIS is losing territory at home, it’s gaining it abroad. Its nimble social-media campaign resonates with a tiny minority of Muslims around the globe. The group has staked its black flag in parts of Afghanistan, Algeria, Egypt, Libya, Nigeria, Pakistan, Russia, Saudi Arabia and Yemen. U.S. intelligence fears that Bangladesh, Indonesia, Somalia and Tunisia could be next. “They are clearly able to execute their global strategy, because they’re expanding their affiliations and they’re motivating people to kill their fellow citizens,” says Jack Keane, a retired U.S. Army general. “I see them only on the defensive, tactically, in Iraq.”

Battlefield successes mask tougher problems. Divisions between Arabs and Kurds, and Shi’ites and Sunnis, remain deep. Russia’s nearly five-month air war in Syria–which has mostly targeted other rebel groups, not ISIS–has strengthened the regime of President Bashar Assad. Government forces have tightened a noose around rebel-held Aleppo, once Syria’s largest city, worsening the biggest refugee crisis since World War II and potentially giving ISIS more room to operate. Iran continues to grow its influence inside Iraq. The Iraqi army remains a work in progress, and a viable Arab ground force to destroy ISIS inside Syria is nonexistent.

The Kurds are one group that has proved able to fight ISIS, but some Kurds are now at war with Turkey, a key NATO member of the anti-ISIS coalition. “We really can’t have military success without political solutions,” the CIA’s former No. 2 official, Michael Morell, told Congress last month. “That has to come first.” The Pentagon believes that could take decades.

Meanwhile, the long-postponed fight for Mosul is likely at least a year away. As happy as the Pentagon was to see Iraq retake Ramadi, Mosul will be far more challenging. The city’s pre-ISIS population of 1.5 million was more than five times Ramadi’s, and 10,000 ISIS fighters have spent nearly two years digging in to Mosul, far longer than they held Ramadi. The Iraqi counterterrorism force that crossed that bridge into Ramadi was trained by the U.S. between 2003 and 2011, before American troops officially departed Iraq. It isn’t big enough to do the same in Mosul, and newly trained Iraqi troops aren’t as good.

But that bridge remains in place, proof of what the Iraqis can do–with a little help. The bridge will eventually make its way north to Mosul, its original destination. It’ll arrive there along with 1,800 fresh troops from the U.S. Army’s storied 101st Division, who will be training the Iraqi forces needed to storm Mosul. The 101st captured Mosul from Saddam’s government in 2003 and hasn’t been back to Iraq in a decade. “Frankly, I know the 101st has taken Mosul before,” Carter told some of the division’s troops at Fort Campbell, Ky., on Jan. 13. “And you can do it again.” But if the GIs need to do it again, it will mean the war on ISIS is going even worse than it seems.

–With reporting by JARED MALSIN/CAIRO

Contact us at editors@time.com.

This appears in the February 22, 2016 issue of TIME.

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