President Obama's open-ended bombing campaign in Iraq to slow the march of the Islamic State of Iraq and Syria (ISIS) has raised questions about how involved the U.S. is willing to get in a deepening sectarian conflict.
The militia group has taken control of large swaths of Iraq over the past year, filling the void left by a lack of government in far-flung municipalities in the north of the country.
Despite the brutality of the militants' advance, ISIS has not threatened any significant U.S. interests in the region. But the administration isn't waiting for that to happen.
"We will protect our American citizens in Iraq, whether they’re diplomats, civilians or military," President Obama said on Saturday. "If these terrorists threaten our facilities or our personnel, we will take action to protect our people."
Particularly, Obama is worried about militants attacking Erbil, a Kurdish city that is home to U.S. diplomats and business people, as well as a burgeoning oil industry.
When it comes to U.S. interests in the region, Erbil shouldn't be Obama's only concern. Analysts consulted by Fusion say the U.S. could be forced to expand the scope of its military involvement in Iraq if ISIS attacks the following strategic sites.
Baghdad is the heart of the American presence in Iraq. The U.S. embassy there is the largest American embassy in the world, and was the most expensive to construct, costing $700 million.
In the unlikely event that ISIS militants attack the city, it could deal a serious blow to the Iraqi government, according to Thomas Donnelly, a military expert and a resident fellow at the American Enterprise Institute, a conservative think tank. "These guys are now operating on several fronts outside Baghdad, so I suppose it's not inconceivable that they could actually fight their way in."
Source: Google Fusion Tables
Rather than target Baghdad's well-protected "green zone" or the international airport, militants could try to take control of certain "choke points" along various approaches to the city, Donnelly said. If militants took control of a route to the south, the Shia heartland, ISIS could block southern militias from aiding the government in Baghdad, he said.
Oil fields in Kirkuk
Kirkuk, a militant-dominated region north of Baghdad, could be another potential target for ISIS, according to Mohamad Bazzi, associate professor of journalism at New York University and former Middle East Bureau chief at Newsday. The Kirkuk oil fields are the second largest in Iraq, and one of the most productive in the world.
Militants attacked the city in July, but Kurdish forces repelled the offensive. The Kurds, an ethnic group in northern Iraq, now control one of the world's most valuable oil reserves.
Taking the oil fields would be a steep challenge for ISIS, according to Bazzi. "The Kurds have invested a lot of resources in protecting Kirkuk and the oil fields around Kirkuk," he said.
Earlier this summer, ISIS spokesperson Abu Mohammed al-Adnani said that the group intended to take control of the southern Iraqi cities of Karbala and Najaf. The reason: both cities contain Islamic shrines that are important to Shia Muslims. A victory in one of those places could win over Sunnis in Iraq, who share a common sect of Islam with the militants.
But ISIS would need to advance from Iraq's western Anbar province to launch an attack. "That hasn't happened yet, and there haven't really been indications that will happen," Bazzi said. "But not many expected ISIS to move toward Kurdish territory, so they might have some surprises."
The city of Samarra, in northern Iraq, could be an easier target. Like Karbala and Najaf, it's also home to a sacred Shia site, the Al-Askari Shrine. The shrine in Samarra has been a flashpoint for conflict during the war in Iraq. In 2006, its golden dome was destroyed by a powerful bomb blast, leading to fierce sectarian battles between Shiite and Sunni Muslims in the city.
Samarra also has a large Sunni population, which could make it more receptive to ISIS militants. The jihadists have a track record for attacking religious sites. In late July, they destroyed the tomb of Jonah, a holy site for Christians, Jews and Muslims in the northern Iraqi city of Mosul.
ISIS has spent months seizing cities and towns in Iraq, but it does not control the most strategic and valuable land in the country. Analysts say it was unlikely the militants could have taken Baghdad before U.S. involvement, and those odds are even slimmer now.
That said, ISIS could still make life difficult for the Shia-controlled government by attacking pipelines and airfields, according to Michael O'Hanlon, a senior fellow at the Brookings Institution. Such a strategy could help them gain support from Sunnis, who would like more power in the government but wouldn't be satisfied with the fractured areas that ISIS currently controls, which O'Hanlon says is "effectively a Sunni ghetto."
"Those parts of Iraq don't really have much oil," he said. "They're important Sunni homelands and they can be culturally, historically and anthropologically important, but they don't really bring the power and the resources that the Sunni tribes want."
O'Hanlon thinks that ISIS could turn to smaller-scale terrorist attacks to shake confidence in the already wobbly Iraqi government. In that scenario, the U.S. may decide to take targeted airstrikes to quash militant actions.