Kurdish rebels in northern Syria walk near the devastated town of Kobani last November. The U.S. bombing campaign helped the Kurds push back the Islamic State from the area. But overall, the U.S. operation against ISIS in Iraq and Syria has shown only limited gains in the past year. Jake Simkin/AP hide caption

itoggle caption Jake Simkin/AP

U.S. Marines arrive at Saudi Arabia's Dhahran Air Base on Aug. 21, 1990. The U.S. began a buildup in the region just days after Iraq invaded Kuwait on Aug. 2 of that year. The U.S. military has been active in Iraq virtually nonstop for the past quarter-century. Gerard Fouet/AFP/Getty Images hide caption

itoggle caption Gerard Fouet/AFP/Getty Images

Iraqi Kurdish singer Helly Luv sings in support of Kurdish fighters, called the peshmerga, who are battling the Islamic State. Her songs are popular among Kurds in northern Iraq, though some critics say her outfits and dancing are un-Islamic. Safin Hamed/AFP/Getty Images hide caption

itoggle caption Safin Hamed/AFP/Getty Images

Iraqi workers clean the site of a truck bomb attack that hit the area a day earlier at Khan bani Saad town, eastern Baghdad, Iraq, on Saturday. At least 115 people were killed in what's described as the single deadliest such attack in the country in a decade. EPA/Landov hide caption

itoggle caption EPA/Landov

Displaced Sunni Iraqis, who fled the violence in Ramadi, arrive at a makeshift camp on the outskirts of Baghdad, in April. Ahmad Al-Rubaye/AFP/Getty Images hide caption

itoggle caption Ahmad Al-Rubaye/AFP/Getty Images

An Iraqi Shiite militia fighter holds a position in Salahuddin province, north of Baghdad, on May 26. With the Iraqi military performing poorly, militias have played an increasingly important role in the fight against the Islamic State. Mohammed Sawaf/AFP/Getty Images hide caption

itoggle caption Mohammed Sawaf/AFP/Getty Images

Kurdish Peshmerga fighters are separated from Islamic State extremists by only short distances in some places around Mosul in northern Iraq, but there has not been heavy fighting recently or any changes in the front lines. Alice Fordham/NPR hide caption

itoggle caption Alice Fordham/NPR

The Nirgul Tablet. Each digital replication becomes more complete and higher-resolution as the project collects more photos and videos of the artifacts. Project Mosul hide caption

itoggle caption Project Mosul

Iraqi anti-terrorism forces patrol in central Ramadi, Iraq, on April 18. A month later, the city fell to the self-declared Iraqi State. Ayman Oghanna, a journalist who was embedded with Iraqi Special Forces in the city, says the Special Forces are capable precision fighters — but are being asked to fill the role of an entire military. AP hide caption

itoggle caption AP

Defense Secretary Ash Carter testifies on Capitol Hill in Washington earlier this month. In an interview on CNN Sunday, Carter complained that Iraqi forces lacked "the will to fight" the self-declared Islamic State. Manuel Balce Ceneta/AP hide caption

itoggle caption Manuel Balce Ceneta/AP

In this photo released Thursday by a website run by Islamic State militants, damaged Syrian helicopters sit at Palmyra air base, which was captured by ISIS after a battle with the Syrian government forces earlier this week. Uncredited/AP hide caption

itoggle caption Uncredited/AP

President Obama tells The Atlantic that the loss of Ramadi to the self-declared Islamic State is a "setback," but he denies the U.S. is losing to the group. Kathy Willens/AP hide caption

itoggle caption Kathy Willens/AP

A car is engulfed by flames during clashes in Ramadi on Saturday. Islamic State militants drove Iraqi security forces out of the city, which is just 70 miles west of Baghdad. Reuters/Landov hide caption

itoggle caption Reuters/Landov

Jeb Bush continues to struggle to articulate a position on Iraq and separate himself from his brother's most unpopular policy. Ricardo Arduengo/AP hide caption

itoggle caption Ricardo Arduengo/AP

Three men water newly planted trees on March 18 in al-Qosh, an ancient Christian village in northern Iraq. The village emptied out last August as Islamic State fighters approached. But the extremists never entered al-Qosh and the village and residents have returned. The men are watering outside a monastery that dates to the 7th century. Alex Potter for NPR hide caption

itoggle caption Alex Potter for NPR

Scott Skiles, 61, and his son Zach Skiles, 32, had never sat down to talk about Zach's life after his deployment to Iraq --until their recent StoryCorps interview. StoryCorps hide caption

itoggle caption StoryCorps

Izzat Ibrahim al-Douri, a former member of Saddam Hussein's inner circle (shown here in 2002), leads one of the Sunni armed factions helping ISIS in its fight against the Iraqi government. Jassim Mohammed/AP hide caption

itoggle caption Jassim Mohammed/AP