ISIS Syria
A resident of Tabqa city touring the streets on a motorcycle waves an Islamist flag in celebration after Islamic State militants took over Syria's air base in nearby Raqqa city, Aug. 24, 2014. Reuters

The U.S. is conducting surveillance missions over Syria as President Barack Obama weighs whether to launch airstrikes against Islamic State militants. Congress has signaled it would support the president should he decide to carry out a military operation against the militant group formerly known as ISIS, although Obama could also move forward without consulting Congress, as reported by Time. The administration has already said it won’t seek permission from Syrian President Bashar Assad, whose government is not recognized by America. Whatever the case, airstrikes against the Islamic State in Syria constitute a situation different from the ongoing airstrikes against the militant group in Iraq. Here are the reasons for -- and against -- attacks on ISIS in Syria.

Why Obama Will Authorize Airstrikes

1) ISIS Is Expanding

Airstrikes will aim to stop ISIS’ advance in Syria, where the Sunni militant group has a strong base in Raqqa, in the eastern part of the country, near Iraq. It also controls several military bases, and ISIS was among the rebel groups that took control of a Syrian border crossing, expanding the group’s reach from eastern Syria to within 200 yards of Israel, according to the New York Times.

2) Calls For Airstrikes Are Growing

The beheading of U.S. journalist James Foley at the hands of ISIS last week and the fears that as many as 140 Americans are fighting alongside the group has prompted political leaders to push the case for action.

“One of the key decisions the president is going to have to make is air power in Syria. We cannot give [ISIS] a base of operations,” U.S. Sen. John McCain, R-Arizona, told Fox News.

U.S. Sen. Lindsey Graham, R-S.C., went even further, saying on CNN he would support a ground operation in Syria should military leaders believe it’s a viable strategy.

3) Airstrikes Will Stabilize Syria

Assad’s government is increasingly being viewed as the lesser of two evils, as BuzzFeed noted. While the U.S. views Assad as an adversary, having him in power is arguably a lower threat to America than is having ISIS in power.

4) The U.S. Is Already Striking ISIS

The airstrike campaign in Iraq is already targeting the Islamic State. If the goal is stop ISIS’ advances, Syria would have to be part of the plan. It’s hard to justify going after the militant group in Iraq, but not in Syria.

5) To Stop An Attack On U.S. Soil

Although the Pentagon has said the Islamic State doesn’t have the capability to carry out terrorist attacks on America on the scale of those on Sept. 11, 2001, the Obama administration is concerned about Western members of ISIS striking on U.S. soil.

“We are concerned, and our allies are concerned, about the risk that is posed by those individuals returning to the West and carrying out violent actions in the West that could be aimed at Western targets,” White House press secretary Josh Earnest said Tuesday.

Why Obama Will Not Authorize Airstrikes

1) Lack Of Intelligence

Airstrikes in Iraq have been guided by intelligence from Kurdish forces and the Iraqi military. As Reuters reported, the same kind of reliable intelligence doesn’t exist in Syria, where moderate rebel groups lack that sophistication and aren’t as a viable force as ISIS.

“I haven’t seen a compelling case yet. And I’m not sure the White House can make one for what strikes in Syria at this point would accomplish. ... We don’t have anybody on the ground that can really work with us the way the Kurds and the [Kurdish] Peshmerga [forces] work with us, the way the Iraqi government can work with us,” U.S. Rep. Adam Schiff of California, the top Democrat on the House of Representatives Intelligence Committee, said during an appearance on Fox News.

2) Higher Risk Of Casualties

The intelligence gap also means an increased risk of civilian casualties, which would only lessen America’s already low standing in the Middle East and embolden ISIS.

3) The Air Defenses Of Syria And ISIS

Both the Syrian government and ISIS have air-defense systems that could pose a threat to U.S. planes conducting airstrikes. There’s no way to tell whether Assad would use his air defenses, especially when ISIS is the target of U.S. operations, but ISIS surely will assuming it has advanced anti-aircraft weapons, as some experts believe.

“Flying aircraft over Syria is very different than in Iraq,” Eric Thompson, senior strategic studies analyst at the Center for Naval Analyses, told Reuters. “There are more sophisticated air defenses, some in the hands of ISIS.”

4) Airstrikes Against ISIS Strengthen Assad

If the U.S. conducted airstrikes against ISIS in Syria, it will be to the benefit of Assad. It’s the stated policy of the U.S. to see Assad ousted from power. In this context, the strike would be a major contradiction of U.S. foreign policy.

5) Public Opinion

With an ongoing war in Afghanistan in its 13th year and the U.S. increasing its military involvement in Iraq, it’s unclear whether the American people can stomach another U.S. intervention in the Middle East.