News from Mosul yesterday regarding the advance of Islamic State of Iraq and Sham (ISIL) is an important turning point not only in the resurgent civil war in Iraq but also for the future of the conflict in Syria. Regardless of how long they can control this city, ISIL will be a major issue to be considered in calculations regarding the future of the region.Since the advance of the civil war in Syria, more than its activities in Iraq, ISIL's operations in Syria have been on the agenda. The increasing strength of the group has been a source of concern that every observer of regional politics has been talking about but none of the international actors wanted to confront this reality. Historical analogies have been provided on how intervention led to the emergence of radical groups and somehow inaction and non-intervention in the Syrian crISIL was considered a way to avoid the rise of such a problem.Now with its latest military gain, ISIL has proved to be a major variable in determining the future of conflicts in the region and its advance touches multiple geopolitical nerves in the region at the same time. First of all, ISIL's advance has made it a significant actor in the region. Although its strength in some Iraqi cities and in the conflict in Syria have been known, with the attack in Mosul they demonstrated their power projection capability in this extremely unstable region. It is highly likely that they will continue some of their advances in other Sunni cities of Iraq and irritate Shia groups, which on the one hand may provide more resources and operational sophistication for ISIL and on the other hand may aggravate the sectarian fault line in the country. It is not very clear however at this point, how long they can keep control of these major urban centers (the initial reported numbers of ISIL fighters that captured these cities shows that it is not sustainable for ISIL to keep control of major urban centers) and how this operational success in Iraq will reflect on the conflict in Syria.With the occupation of Mosul, ISIL acquired a lot of money and ammunition and a possible transfer of some of these resources to Syria may change the situation on the ground and increase the power of ISIL in comparison to other organizations.The attack on Mosul and the fall of the second-largest city in Iraq may also have some serious consequences regarding the future of international and regional relations in the region.ISIL with its activity in Syria has become a more transnational threat to stability in the region, which necessitates the partnership of different groups and states to deal with. Under the current circumstances, the attack on Mosul may change relations between the Kurdish Regional Government and Iraqi central government and force them to cooperate regarding security matters in the future. At the same time a potential attack or threat by ISIL on other cities in Northern Iraq, including Kirkuk and a possible hostage crISIL involving Turkish truck drivers may lead to a rapprochement of the Iraqi government with Turkey as well in terms of security. If ISIL increases its operational capability in urban centers some other international actors may also contribute to the effort to deal with this threat.However, despite the possibility of all these interregional and international partnerships, it is not very clear how to deal with an organization such as ISIL effectively without further destabilization in the region. Especially within Iraq the composition of ISIL has been evolving and the demographics and the recruitment of the organization is changing throughout conflict. The estimates regarding the number of ISIL fighters show an increase while Iraqi government keeps failing to control the situation. Recent reports demonstrate that the organization also is modifying its tactics and procedures on the ground and aiming to control and administer the regions instead of only organizing destabilizing destructive attacks.Although some consider ISIL to be primarily a threat to the countries in the region, the emergence of a failed region in the midst of the Middle East will present a major threat to international security as well. "To pick a lesser evil" and let Assad rule the country and fight with ISIL proved to be a failed strategy. In particular, the claim by ISIL of being a "state" and its rapid evolution makes a revision of current methodologies of dealing with non-state security threats a necessity. Although it seems difficult to come up with a strategy to contain the Syrian and Iraqi operations of ISIL, at the same time it is necessary for the international community to take action in Syria to end the bloodshed, an important first step to slowing the growth of this threat. This of course has to be followed up with a comprehensive capacity- building strategy and a new counterinsurgency strategy by local security forces.