August has seen important developments in the Syrian conflict. Turkey has granted air base access to the United States in its struggle against the extremist group known as the Islamic State, Iran has launched fresh diplomatic initiatives in Beirut and Damascus, and Russia has held talks with Gulf countries and the United States. Beyond the fog of war, the intricacies of domestic politics, and the secrets of diplomacy, what are the fundamentals of stopping the bloodshed in Syria?

In spite of this rapidly evolving environment, the road to a political agreement remains long and bumpy, as the various actors’ priorities diverge widely. However, three fundamentals stand out at this point in time:

Shifting Tides on a Fragmented Battlefield

For more than four years, true to its decades-long history of authoritarian rule, the Assad regime has shown a limitless ability to exert violence. But although power rests with the Assad family and a small number of mostly Alawite allies—including the Makhlouf family from which President Bashar al-Assad’s mother hails—they depend on a vastly larger structure of allied factions, Baath Party loyalists, and state and military institutions to remain in power.

The Syrian armed forces are exhausted and have recently lost territory. But the army remains resilient, thanks to continuous resupplies from Russia, strong Iranian backing (including military commanders and thousands of fighters on the ground), and the aid of thousands of fighters from pro-Iranian Shia militias like the Lebanese Hezbollah. Predictably, the Assad regime has clung to the only two regions it truly cares about: the Latakia-Tartus region on the coast, cradle of the Alawites and the Assad family, and Damascus, the capital. By contrast, the regime has never paid much attention to the Kurds, concentrated on the border with Turkey.

In a future transition, according to this logic, it is conceivable that the regime would accept a restriction of its political authority to the Latakia–Damascus corridor, while a patchwork of administrative arrangements would govern the rest of the country. The current coexistence of Kurdish and Baathist administrative and military powers in the Qamishli-Hasakah region is a good example.

The Contenders for Power in Syria

The question is, then, which actors will dominate the battlefield as this gradual internal division of Syria takes shape?

The Syrian Kurds are the real novelty of this civil war. They are now led by groups linked to the pan-Kurdish militant group known as the Kurdistan Workers’ Party, or PKK, including the People’s Protection Units (YPG). Under threat of total cleansing by the Islamic State, the YPG has proved to be the only force capable of real success on the ground, at least when provided with close air support from the United States. Although the YPG has refrained from attacking west of the Euphrates River (because a Kurdish expansion in that direction was opposed by Ankara with Washington’s acquiescence), the Syrian Kurds have established themselves as a political and military force to be reckoned with in any future political agreement—albeit one mainly focused on their own areas.

By contrast, the so-called moderate opposition forces trained by the U.S.-led international coalition in Turkey have proven to be a miserable failure, if not a tragic joke. So far, a new Pentagon-led training program has produced only about 60 fighters, against an objective of 15,000 over three years, and many of them were captured by al-Qaeda as soon as they set foot in Syria. It may well be that in a land of unstable and shifting alliances, “vetting” moderate rebels is an impossible task. Although this project is supported by Turkey and Saudi Arabia, it may prove a squandered investment from a U.S. standpoint.

However, various Sunni Islamists and other anti-Assad rebel groups that are not necessarily directly supported by the United States itself, but in many cases linked to Saudi Arabia, Qatar, Turkey, or other U.S. allies, remain a powerful presence on the battlefield. Unlike the YPG and so far also the Islamic State, which is largely confined to Syria’s eastern desert, these groups confront Assad’s regime in the heavily populated western parts of Syria, including in major cities like Damascus and Aleppo. Much will depend on how regional actors choose to deal with these disparate forces, which range from Sunni conservative and soft Islamist groups fighting under the Free Syrian Army banner in southern Syria and elsewhere, to hardline Islamist groups like Ahrar al-Sham and the al-Qaeda-aligned Nusra Front.

The Regional Game

During the four years of conflict, Russia has consistently resupplied the Syrian regime with ammunition and spare parts, effectively keeping it afloat. Since the beginning of Baath Party rule in 1963, there has been a strong political relationship and military alliance between the two countries. Moscow is no doubt keen on keeping that bond, but it is also worried about the involvement of Chechen jihadists with the Islamic State and al-Qaeda, something that could have serious consequences back home.

The more innovative regional partner may instead be Iran. There is much speculation about Iranian Foreign Affairs Minister Mohammad Javad Zarif’s peace plan for Syria, but caution is in order for a simple reason: Tehran will be adamant both to exert leadership in the “Shia crescent” that links Tehran, Baghdad, Damascus, and Hezbollah in Lebanon and to keep delivering weapons and missiles to Hezbollah through Damascus airports. So, whatever the expectations, Tehran will continue to need an ally in Damascus, if not Assad himself. Iran is back on the international stage after signing the nuclear deal, but it is not back in modesty. It will want to play its cards.

The United States, for its part, has just gained access to three Turkish air force bases. From a narrow military standpoint, this is a major shift toward increased efficiency (shorter flights to northern Syria, the possibility of standby flights over allied territory, and quicker aircraft turnaround times), decreased cost (due to shorter distances and less midair refueling), and increased safety (search-and-rescue missions from allied territory). Coalition aircraft operating out of Turkey might be able to bar the Islamic State’s access to its main gateway to the outside world: southeastern Turkey. But, as important as this is, it does not guarantee that the Islamic State will be defeated. It is equally important to convince or push Turkey to do its part in sealing its remaining border with the Islamic State.

However, Ankara remains single-mindedly focused on the PKK, which has been fighting the Turkish government since the late 1970s. The new Turkish air campaign has mostly targeted Kurdish positions rather than the Islamic State. This is partly due to the Turkish leadership’s unease over Kurdish forces gaining ground in northern Syria, following the YPG victory in Kobane this spring and the unification of two of three Syrian Kurdish enclaves, but purely domestic politics also play a part.

The June 7, 2015, electoral gains in Turkey by the Peoples’ Democratic Party, or HDP, which the government says is linked to the PKK, has made the Kurds the main impediment to Turkish President Recep Tayyip Erdoğan’s march toward a super-executive presidential system. Disturbingly, the president now seems to let his own electoral calculations dictate Turkey’s foreign policy. Defending itself against terrorism is a legitimate objective for Turkey, but when the Turkish leadership suddenly replaces years of restraint and a Kurdish peace process with an all-out military campaign, it brings about high risks for the country as a whole and a considerable sense of unease for Ankara’s allies.

The Elusive Contours of a Compromise

In this regional context, Turkey’s and Saudi Arabia’s continued insistence on Assad’s departure from power has become something of an isolated stance. It has created fresh tension between Ankara and Tehran, and while the U.S. and European governments also claim to be committed to Assad’s removal, their first priority is to contain and undermine the Islamic State.

Here, the bottom line is fairly straightforward: no lasting agreement on the future of Syria will be reached without Russian and Iranian consent, that is, without preserving a large part of the Syrian administrative and military structure, if not keeping Assad himself in the short term. All actors, Europeans included, will have to adjust their initial policies if they want to bring about an agreement on the future of Syria. The question is whether they will be able to get their Syrian and regional allies on board with such a strategy, and whether Iran can become a trusted interlocutor in the region’s politics.