If someone had told Barack Obama as a presidential candidate in 2008, that in August of 2014, five and a half years after taking office as a result of a campaign in large part victorious because of its anti-war message, he would be ordering the return of U.S. troops to Iraq, he would have taken the remark as an insult or laughed out loud. And nevertheless, that is exactly what he has just done, twice over: by bombing certain Islamic State group positions in northern Iraq, and by sending 130 soldiers to assess the plight of the thousands of Yazidis trapped in the Sinjar Mountains in order to organize a humanitarian mission.

But the question on everyone’s mind is, will this be enough? Deputy National Security Adviser Benjamin Rhodes presented the first signs that it will not be by leaving open the possibility of using military troops for a rescue operation that would include the right to defend against possible jihadi attacks. Yet unspoken but buzzing louder in everyone´s conscience, starting with the president´s, is the possibility of intervention with more permanent and complex combat missions against the jihadi enemy that has turned Iraqi reality on its head.

Thus, the issue that defined Obama´s electoral victory could define his legacy. But not in the way he intended, back in February 2009, when he announced an 18-month plan to pull U.S. forces out of Iraq, a goal he accomplished when the last American soldier left the country on Dec. 18, 2011. Instead, Iraq could define Obama´s legacy by entangling the United States in a new war with ancient Mesopotamia or by permitting the territorial takeover of Iraq by the armies of Abu Bakr al-Baghdadi, the self-proclaimed Caliph of Iraq and the Levant. If the first occurs, it will destroy Obama´s credibility; if the second occurs, it will destroy the credibility of a nation that gambled its superpower prestige during a decade-long fight against terror and exportation of freedom to the Middle East.

The government has insisted that it does not have plans to send troops on a combat mission, but let´s be serious: when the United States begins a military operation that doesn't accomplish its goal, it will inevitably continue the operation until it achieves its objective, or, at least until it appears to do so. And the first to admit that the bombings against Islamic State group positions in northern Iraq have not proven effective has been Lieutenant General William Mayville, director for operations of the Joint Chiefs of Staff. Preparing the ground for what may follow, he has stated clearly: “I in no way want to suggest that we have effectively contained or that we are somehow breaking the momentum of the threat posed by ISIL. They're very well-organized. They are very well-equipped. They coordinate their operations. And they have thus far shown the ability to attack on multiple axes.”

Lieutenant General Mayville remarks that the bombings, carried out by F-18 jets of the U.S. Air Force in order to stop the Islamic State group from devastating the Kurdish defense in Erbil (the capital city of Iraqi Kurdistan) and consequently adding another strategic city to its caliphate have actually accomplished very little. It was a very limited operation: not only did it fail to force a retreat of the jihadi forces, but it barely slowed down their attempt to capture Erbil. Abu Bakr al-Baghdadi knows very well that the U.S. and Kurdish combatants (the celebrated “Peshmergas”), both veterans of the fight against Saddam Hussein, have turned out to be much less effective against his jihadis than what he originally imagined. In fact, Baghdadi has forced them to retreat from various positions, just as Iraqi Army soldiers did before. Baghdadi calculates, accordingly, that unless the United States decides to stage a more substantial intervention — something that would convert Baghdadi into a hero of the resistance, a leader fighting against an external aggressor — time is on his side.

For the moment, the humanitarian drama developing in the Sinjar Mountains possesses such a powerful moral element that no one in the West will question the actions of the United States regarding the rescue of the Yazidis, who remain trapped in the mountains after having fled the city in terror from Islamic State group attacks. The horrifying accounts that have spread around the globe and that describe a genocide underway of the Yazidi “devil-worshipers” at the hands of Baghdadi´s fanatical Sunni supporters, are enough for the world to have reached a consensus on the need to act. As a result, the Pope has supported the U.S. bombings, and Germany, traditionally resistant to any form of intervention, has offered to give non-lethal aid to whomever fights against the Islamic State, not to mention the provision of French weapons. But it´s one thing to drop food and water from the air and to supply weapons to Baghdadi´s enemies, and another thing entirely to stage a direct intervention to rescue thousands of victims — an operation that would inevitably involve military risks. And where exactly are the limits to this operation? Where do they start and where do they end? If this operation manages to free thousands of Yazidis from the snare in which they are trapped, will it also assume the responsibility of protecting them from retaliation? Will it provide them with a safe haven? Lest we forget, this crisis involves people who have fled their homes and are adrift in the world.

One factor that complicates this hellish scene is the absence of a trustworthy Iraqi government through which the West could act. After various months of struggle, the United States has succeeded in removing Nouri al-Maliki, who attempted to remain in power after two terms as prime minister. According to multiple testimonies, Maliki has been highly responsible for dismantling the democratic framework that was beginning to take hold in Iraq and for stirring up old disputes with renewed force. Not only did he govern despotically with support from like-minded factions, but his administration was also extremely ethnically exclusive. Instead of encouraging Sunnis and Shiites to live together, instead of starting a dialogue among the warring Shiite groups, he fanned the fire of hate between them. As a result, the more organized group, the Islamic State of Iraq and the Levant, formerly a part of al-Qaida´s support coalition, found space in the distressed country to grow strong.

Now, another moderate Shiite, Haider al-Abadi, has been appointed by President Foaud Masoum, a Kurd of the former government. Abadi belongs to the same party as Maliki, but in contrast, Abadi has pluralistic support, including the militia of the Shiite cleric Moqtada Sadr, a declared enemy of the outgoing administration.

Maliki is reluctant to leave his position, however, and has attempted to organize a resistance with his own militia, although at this point he doesn't seem to be an important threat. The greater problem is that the new government is not functioning yet and will take a while to establish itself. To complicate things further, the Kurdistan zone in northern Iraq, where Islamic State group forces intend to gain power, is under control of a regional government that has been winning its autonomy as Baghdad has been dissolving into chaos and losing authority over distant regions. Any attempt by Baghdad to cut off this autonomy will be answered by the Kurds, who have spent many years opposing the capital´s power. However, if the West focuses its aid on the regional Kurdish government, a logical choice since the jihadi threat is currently located there, it could accelerate the process of virtual Iraqi Kurdistan independence, which is the medium term goal of its current authorities, according to well informed observers.

The international situation is no less complicated. Fear of Baghdadi has caused two bitter enemies, Saudi Arabia and Iran, to support Abadi as the new prime minister. Shiite Iran is a natural enemy of Sunni jihadism, while Saudi Arabia knows it will be the next target of Baghdadi´s plan, like Osama bin Laden´s before him, to overthrow the Arab monarchies he considers corrupt and run by the devil. This creates an agonizing dilemma for the United States and Europe. One the one hand, forming an alliance with Iran to confront the greater danger, the Islamic State, could reinforce radical Shiites in Iraq, Assad´s dictatorship in Syria, and Hezbollah´s powerful Shiite militia in Lebanon. On the other, not joining forces with Iran could damage the effort to unite the Shiites against Sunni jihadism.

Obama is aware — as his prudence testifies in these tense moments — that every action in this zone can trigger counterproductive reactions that could turn on him. The Islamic State was, in part, a beneficiary of the international mobilization against Assad in Syria. Even though the Islamic State did not receive direct aid from the United States (which concentrated its support in the moderate sectors of the fight against the Druze dictator), Turkey did receive aid, and then provided the Islamic State with a sanctuary on the Syrian border that Baghdadi utilized to acquire supplies and to penetrate into Syrian territory.

Baghdadi — a radical born in the early 1970s, with a doctorate from the University of Baghdad, who proclaimed himself leader of the Islamic State of Iraq and the Levant in 2010 and rebelled against Ayman al-Zawahiri, the successor to Bin Laden, whom his group supported — has a clear objective. He wishes to reunite Iraq and the Levant (the Arab states that the United Kingdom and France converted into the current separate nations of Syria, Jordan and Lebanon, together with Palestine and part of Sinai) into a vast caliphate under his control.

For the time being, he has managed to dominate important parts of Syria (where he controls the petroleum resources of Deir al Zur and maintains his principal base in Raqqa) and Iraq (where his central hub is in Mosul, the second largest city of the country, which he captured in June). He possesses weapons stolen from the Syrian and Iraqi armies, and, according to Jessica Lewis, a former intelligence agent of the U.S. Army and now affiliated with The Institute for the Study of War, he controls seven divisions of the country, including one near Baghdad and another in the south of the country, far from where he has had a strong presence until now.

His bloodthirsty savagery is already a regional legend, and he has managed to control many places due to stories of his cruelty that inspire terror and frighten the defendants of those lands into retreat. Precisely for that reason, the United States bombed Islamic State group positions a few days ago near Erbil, the capital of Kurdistan that appeared to be on the brink of defeat. Many Kurdish soldiers have now fled or are preparing to do so.

To stop this self-proclaimed Caliph, Obama will have to employ something more than limited bombings and humanitarian operations, unless all of the Iraqi factions — a true miracle — unite themselves against the jihadis and become more effective fighters than they have ever been. And still, in that case, there´s no guarantee of anything. Almost three years after U.S. withdrawal, Obama returns to Iraq against all of his instincts and deepest convictions.