Istanbul(CNN) It has been more than a week since a coalition of Iraqi government and Kurdish Peshmerga ground troops backed by US and allied aircraft launched an offensive against ISIS forces in the Iraqi city of Mosul.
The US defense secretary Ashton Carter announced this week that the anti-ISIS coalition will move with the "same sense of urgency" to surround the other ISIS stronghold in Raqqa, located across the border in northern Syria.
In some respects, Raqqa could be considered a far easier military objective. It is much smaller than Mosul, with far fewer civilians at risk of being made homeless, or caught in the crossfire of a protracted urban battle.
The biggest challenge is finding troops to bring the fight on the ground against ISIS.
Iraq, despite its long history of conflict, is far more stable than Syria. There is an Iraqi central government with security forces that largely cooperate with the semi-autonomous Iraqi Kurdistan regional government against their common ISIS enemy.
Syria, however, is a patchwork of multiple conflicts being simultaneously fought between a dizzying array of armed groups. Each faction seems to enjoy the support of rival foreign patrons.
While Washington says its main objective is to eliminate ISIS in Syria, the Syrian government and Syrian rebels are far more busy trying to eliminate each other.
It is hard to conceive how the US can convince these warring factions to stop killing each other and instead somehow unite to focus on defeating ISIS.
Read: ISIS sends 'suicide squads' to Iraqi stronghold
Almost of the local and international actors involved in the Syrian Civil War see ISIS as a deadly threat.
This includes Syrian armed-opposition groups, the Syrian government, Kurdish militias and regional powers like the US, Iran, Turkey and Russia.
The problem, again, is that most of these armed factions and their international supporters are too busy fighting each other to concentrate on ISIS.
The vacuum created by the civil war is what allowed ISIS to take root in Syria in the first place.
As long as the war continues, ISIS will capitalize on its enemies' distraction to consolidate control over its own territory.
Presumably, the Syrian government -- which claims to want to reunite the fractured country under its authority -- would lead a proposed offensive against a nihilistic movement like ISIS.
However, the government of Bashar al-Assad has been at war with his own people for five straight years.
Throughout this conflict, the military has suffered untold casualties and large-scale desertions. Many of the young Syrian men who smuggled themselves into Europe over the last two years said they were fleeing mandatory conscription into the armed forces.
Until Russia sent troops and warplanes to support Damascus in 2015, Syrian government forces were losing ground on multiple fronts to both ISIS and the armed Syrian opposition.
Arguably, the Assad regime may have collapsed long ago if not for substantial military and financial assistance from its allies, which also include Iran and Lebanon's Shiite movement, Hezbollah.
The Syrian military is stretched thin. But it has far more tanks and artillery than its enemies on the Syrian battlefield. And there is one additional weapon in the Syrian government arsenal: air power.
But without major help from foreign countries, Damascus' aging fleet of Soviet-era warplanes and helicopters are unlikely to make a major dent in ISIS' defenses.
Far more modern US, Russian, and Turkish fighter jets have only succeeded in damaging, but not permanently destroying this determined ISIS enemy.
Moscow justified Russia's military intervention into Syria in 2015 partially by arguing that it would go after ISIS.
In March 2016, Syrian government troops backed by Russian air support and artillery succeeded in liberating the ancient desert oasis of Palmyra from ISIS control.
Since then, however, the Russian-Syrian government alliance has appeared far more focused on battling other Syrian rebel groups across the country. These allies have been laying siege for two months to the rebel-controlled part of the Syrian city of Aleppo.
These efforts have reportedly been supported by troops from Iran, fighters from Lebanon's Shiite Hezbollah movement, and even mercenaries from Afghanistan.
The US has been conducting airstrikes against ISIS targets in Iraq and Syria for years. It has also deployed thousands of ground troops in Iraq, as well as small numbers of US special forces in Syria to assist in the anti-ISIS campaign.
A larger US military intervention in Syria involving more ground troops appears unlikely in the final days of the Obama Administration, which historically has tried to avoid deeper entanglement in the Syrian conflict.
The US and assorted European and Middle Eastern allies have a history of training, arming and financing Syrian rebel groups, with mixed results.
In the past, Washington had difficulty convincing rebels to focus on battling ISIS, since many members of the Syrian armed opposition often say the Syrian government poses a much bigger threat to their existence.
Western-backed Syrian rebel groups tried to defeat ISIS in the past. In early 2014, rebels mounted an offensive against ISIS. This "war within a war" ended in a virtual stalemate. Rebel groups maintained control of parts of Syria, while ISIS consolidated control over its own territory, declaring Raqqa as the capital of its self-declared caliphate.
Today, the so-called "moderate" opposition in Syria is struggling to defend itself on multiple fronts from attacks by the Syrian government and its Russian, Iranian and Hezbollah allies.
A staunchly secular Kurdish militia in Syria known as the People's Protection Units, or YPG, has proven to be one of ISIS' deadliest enemies on the ground in Syria.
The Kurds' stiff resistance to the ISIS siege of the border town of Kobane in 2014 prompted the US to send help in the form of airstrikes and weapons.
The Kurdish faction has since succeeded in capturing large swaths of territory from ISIS.
But the rise of the Kurds has also become a complicating factor. Many in Turkey see the establishment of Kurdish "statelets" in northern Syria as a major threat.
The YPG has close links to the Kurdistan Workers' Party, or PKK, Kurdish separatist rebels who have waged a guerrilla war against the state in Turkey for thirty years.
At alternating times the Kurdish militia also has periodically clashed with, and cooperated with, Syrian rebel groups and the Syrian government.
Syria's northern neighbor Turkey is a longtime supporter of the armed Syrian opposition.
In more recent years, Turkey has declared itself an enemy of ISIS. Turkish warplanes periodically bomb ISIS targets in Syria, while also arresting suspected ISIS operatives in Turkey.
In July 2016, Turkish tanks moved into part of northern Syria to establish a "terror-free corridor."
However, Turkey also routinely attacks the YPG in Syria, arguing that the Kurdish militia is as much a threat to Turkish national security as ISIS.
The fact that Turkey, a member of the NATO military alliance, is at war with a faction that the US actively supports underscores how complicated and difficult it will be to create a coalition capable of defeating ISIS in Syria.