Idlib - The fresh clashes in Syria's Idlib region between a dozen important Islamist and extremist rebel movements, are battles for turf and authority on the ground - but they also mirror northern Syria's ever-changing complexities, as local, regional and international actors change policies and tactics.These actors and their aims fluctuate almost on a monthly basis, which helps explain last week's face-off between former al-Qaeda affiliate Jabhat Fateh al-Sham (JFS), on one side, and the independent Islamist movement Ahrar al-Sham and half a dozen smaller allies, on the other.The core battle between JFS and Ahrar al-Sham (AS) flared last week after JFS attacked some smaller Islamist groups that were close to AS, notably Jaish el-Mujahideen. JFS accused them of selling out the revolution against the Syrian government by attending the Russian-Turkish-Iranian-sponsored political talks in Astana, Kazakhstan. It also suspected rebels of passing on JFS locations and coordinates to foreign parties that have recently been bombing JFS.Several smaller Islamist rebel groups found themselves in danger of being destroyed by the much stronger JFS and quickly moved to form a coalition with AS, which, in turn, promised to protect them from JFS attacks. These intra-Islamist rebel tensions increased sharply, in part due to the fallout from the rebel defeat and evacuation of Aleppo and other besieged towns, which pushed more rebels into the Idlib region.Consequently, dozens of small and increasingly vulnerable rebel groups, whether secular or Islamist, face their inevitable moment of reckoning: will they side with the hardline JFS and work towards creating a mini-Islamic state or an emirate, while continuing to fight the Bashar al-Assad regime?Or would they remain as part of the secular-nationalist Free Syrian Army coalition and move closer to AS, the powerful Islamist rebel group that projects itself as more pragmatic and locally anchored than JFS?Post-Aleppo dilemmasRebel groups confront these issues now because regional and international players have changed the entire political and military equation in northern Syria, following Russia, Iran and Hezbollah's successful assistance to Assad in regaining control of Aleppo.Turkey is also actively engaged with local allies in northern Syria, as it simultaneously fights the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) and Kurdish groups that seek a more autonomous region along the Turkish border.Russia and the United States have stepped up their air attacks against some armed groups, including JFS, while Russia, Turkey and Iran have initiated a new political process in Astana that aims to end the entire Syrian war through political negotiations that lead to a new constitution. This follows successful Turkish-Russian mediation to end the Aleppo battle and siege.All these developments have squeezed JFS and AS, who find themselves as the next major target for air and ground attacks by the Syrian government and other regional and global powers. These two groups have worked together in recent years, when they primarily fought ISIS or the Syrian government, including forming a large coalition named Jaish al-Fateh in early 2015 that conquered Idlib.Neither of them attended the Astana talks, which increases their status as likely targets for Turkish, Russian, Iranian or American bombs.All smaller Syrian rebel groups, regardless of their secular, Islamist or extremist orientation, now face the same dilemma: they might be attacked by JFS and other hardline groups if they join political talks to achieve a ceasefire and a new constitution; if they ignore the political talks, they will be attacked militarily by the government and foreign powers, in a severely imbalanced military equation that augurs badly for them, as Aleppo showed.Turkey's involvementComplicating this equation is Turkey's efforts to entice Syrian rebel groups to join its fight against ISIS and autonomy-seeking Kurdish groups in the north, in return for Turkish support and even potential future protection and patronage in a decentralised, new Syria.This highlights the problem that has plagued hundreds of Syrian rebel groups since 2012: unless they unite and coordinate to act jointly on the basis of their collective numbers and local legitimacy and support, they remain easy prey for their more technologically advanced foes, whether the Damascus government, its foreign backers, Turkey or the US.This reality may explain why both JFS and AS now seek to attract or pressure smaller groups to join them - or else they all risk annihilation.OPINION: Syria's Civil War - One conflict, multiple battlesThe attacks last week, especially on Jaish al-Mujahideen, may be only the beginning of a longer campaign by JFS to consolidate its power base, in Idlib especially. AS, for its part, is protecting and bringing into its orbit Jaish al-Mujahideen, Suqour al-Sham, Faylaq al-Sham, and other small groups that have been attacked or threatened by JFS.Whichever of them emerges stronger will face the larger inevitable battle against ISIS, the Syrian government, and foreign powers. Some groups might react to the current evolving environment by slowly shifting from a military to a political battle, hoping to find a place to survive in new forms in a reconfigured Syria that might emerge in the coming years. Whether that happens will be clarified in the months ahead, when new conditions, actors, and tactics will surely emerge, as they have in the past few weeks.Rami Khouri is a senior public policy fellow at the Issam Fares Institute at the American University of Beirut and a non-resident senior fellow at Harvard University Kennedy School.The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.