Three months have passed now since the Islamic State in Iraq and Syria captured the world’s attention by making major territorial gains in northern Iraq, and yet the terrorist group has only continued to flourish and grow in plain sight. ISIS—which is known under a variety of other abbreviations and geographic designations—is characterized by its rapid growth, brutal tactics, and exceptionally radical ideology. The ongoing humanitarian crisis, in addition to the regional threat that the group poses, should prompt a much stronger international military response than is presently occurring.

ISIS has managed to establish clear control over a large region, spanning roughly 90,000 square miles, whose inhabitants are forced to live under the group’s interpretation of Islamic law. In addition to oppressive measures such as mandatory full-body covering for women and expulsion of girls from school, the ISIS regime has also instituted cruel and unusual punishments such as forced amputations for accused criminals. Worst off are religious minorities; atrocities against Iraq’s Zoroastrian Yazidi population have been well-documented in the media, while Christians have subject to forced conversion and mass killing.

These crimes against humanity have been made possible by the Islamic State’s remarkable organizational and operational success. According to estimates cited by the BBC, the group has between 30,000 and 50,000 followers, including 10,000 to 20,000 experienced militants. It also has considerable resources—estimated at over $2 billion—largely accumulated as a result of the looting of Mosul, Iraq’s second-largest city. The group’s income seems likely to increase even further, due to its control of significant oil resources, and its base of wealthy regional donors. Finally, ISIS has armed itself with heavy weaponry and military vehicles left behind by retreating Iraqi forces. Such a deeply established terrorist threat is very unlikely to disappear easily, especially considering the notorious corruption and ineptitude that plagues the Iraqi army.

The United States has taken a few important measures in response to the terrorist threat. In the last month, President Obama has authorized air strikes against ISIS in Iraq which have helped Iraqi forces and Kurdish peshmerga militias win a few victories against the extremists, including the recapture of the Mosul Dam. America, France, Britain, and Germany have also shipped armaments to the Kurdish militias holding back ISIS in the north. Finally, the United States has committed 650 military advisors to provide intelligence and training to the Iraqi Defense Forces.

Positive as they are, these measures are deeply insufficient. Although the group’s rapid advance into Iraq has been slowed, there seems to be little hope in the status quo that Iraqi forces have the capability to reclaim the occupied region, end the humanitarian crisis there, and eliminate the group’s safe haven. This alone should be enough to mandate a more urgent degree of intervention. But there are other dire potential consequences in store if ISIS is allowed to retain its base of operations in Iraq and Syria. Experts have warned that the group poses a threat to neighboring countries including Lebanon and Jordan. The extremists have already attacked along the Lebanese border, even temporarily capturing the town of Arsal near the beginning of August. A passive wait-and-see approach is very rarely good policy in the face of crimes against humanity, and is even more dangerous in light of the Islamic State’s potential to escalate the conflict further.

Thankfully, there are several options available for the president to back up his stern rhetoric against ISIS and to substantively address the threat at hand. First the United States should stop limiting air strikes to the Iraqi side of the practically obsolete Syrian border, and begin striking ISIS targets in both countries. As Indiana Senator Dan Coats of the Homeland Security Appropriations Committee noted in a recent editorial: “Vietnam, Korea, Serbia and our experience along the Afghanistan-Pakistan border have taught us the futility of attacking military forces that have safe-haven bases nearby.” An important, if distasteful, way to combat ISIS’ presence in Syria without committing ground troops there would be to limit aid to the opposition to Bashar al-Assad’s regime, as Assad’s forces constitute the group’s primary opposition. As war correspondent Dexter Filkins noted in a recent New Yorker interview  “it’s a zero-sum game on the ground”—any action that weakens Assad strengthens ISIS and vice versa. The ISIS presence in Iraq grew out of the group’s presence in Syria, and it seems unlikely that the battle in Iraq can be won if Syria is left to fester.
Most importantly, the United States and its allies should be open to committing combat troops and Special Forces in Iraq to spearhead a counteroffensive against ISIS. Secretary of State John Kerry, among others, has acknowledged that air strikes alone will not solve the problem. Kurdish forces are hard-pressed even to defend their own tribal areas, and the shaky state of the Iraqi military, as previously noted, precludes them from reversing ISIS’ territorial gains any time soon.  “A would be very difficult without U.S. ground forces or ground forces of others,” former Iraq War general Carter Hamm noted in an interview with ABC. A prudent recommitment of American troops or the formation of an international military coalition must happen sooner or later for the conflict to be extinguished, and the world cannot afford to wait.