Vladimir Putin and Recep Tayyip Erdogan, as much as any two men outside of Syria, are in a position to decide what else the country must endure.
Two years on, fate of Syria in Russian and Turkish hands
Today is the second anniversary of the start of the Syrian uprising, the "Day of Rage" when peaceful demonstrations erupted all over the country. The tragic descent into civil war after the Assad regime opened fire on unarmed demonstrators is well known. As is the desperate plight of the Syrian people, now fleeing at a rate of 2,000 a day.
What is not clear is how the bloodshed and destruction can be brought to an end.
One thing which distinguishes Syria from conflicts over the past decade is the absence from the battlefield of two of the region's main powers. The US president, Barack Obama, is sitting in his tent, having made clear that he wants no more Middle Eastern entanglements and is not even willing to arm the rebels. As for Israel, its concern is that chemical weapons fall into the hands of armed groups.
Thus the two most prominent actors are president Vladimir Putin of Russia, firm ally of the Syrian president, Bashar Al Assad, and the Turkish prime minister, Recep Tayyip Erdogan, one-time friend of Mr Assad and now ardent proponent of his removal by force.
Hopes for a quick end to the fighting have often centred on Mr Erdogan, amid suggestions from Ankara that the Russians might be about to give ground and pave the way for regime change. When he and Mr Putin meet, they embrace warmly, but there has been no sign of Russian support for its ally crumbling.
There are some similarities between the two men. Both have transformed their countries: Mr Putin restored order and prosperity to Russia after the chaos of the Yeltsin years, establishing in the process what he calls "sovereign democracy" in a de facto one-party state under his personal control. As for Mr Erdogan, he has reconciled the secular Turkish republic with its Islamic roots, established civilian control over the military and set his mind on making his country once again a regional power.
Are these two the men to end the war and create a post-Assad Syria? The answer is probably no.
Mr Putin's world view is shaped by his KGB training and he sees Russia as surrounded by enemies ready to pounce on the slightest sign of weakness. He fought for years, at the cost of tens of thousands of dead and the destruction of the city of Grozny, to stop the tiny territory of Chechnya seceding.
To have lost the smallest patch of Russian territory would have shown weakness, thus encouraging China to think that Russia's sparsely populated and resource-rich Far Eastern territories were up for grabs. Any United Nations-sanctioned regime change - such as the toppling of Muammar Qaddafi in Libya - is seen as a precedent for Washington to remove him.
Political demonstrations, even peaceful ones, are viewed through the template of the Orange Revolution which, thanks to generous financial support from Russia's enemies, came close to wresting Ukraine from the Kremlin's orbit. By definition they are foreign-funded treachery.
Fiona Hill, author of a new biography, Mr Putin: Operative in the Kremlin, believes that the Russian leader's plan has been to give Mr Assad all the time he needs to crush the opposition, just as Mr Putin was able to overcome the Chechen separatists.
The Russian leader, she says, is not a vote-chasing politician but a representative of "the deep state", a term used to described the network of top-level security, military and legal officials who are said to have run Turkey in secret for decades in the pre-Erdogan era.
"Putin is the kind of person who thinks any sacrifice is worth it," she writes. "But Erdogan is a retail politician. He cannot afford to see people dying at home or even abroad. Particularly people for whom there is a degree of kinship.
"Erdogan is desperately trying to figure out some form of solution in Syria ... Putin has all the patience to see events play out. What worries him is not the bloodshed but the collapse of Syria, and the knock-on effects of that further afield."
Mr Erdogan is indeed not a man to wait. At the start of the uprising, he raised his standard to appeal for allies to put a quick end to the Assad regime. The Americans refused to budge.
Now, seeing the break-up of Syria and the emergence of an ungoverned Kurdish area on his border, he has set out on an even more ambitious path: to reconcile Turkey's Kurdish minority - perhaps one fifth of the population - with the Turkish Republic under a new constitution. To that end negotiations have opened with Abdullah Ocalan, the jailed leader of the Kurdistan Workers Party (PKK) which has been fighting the Turkish state for almost 30 years.
It is hard to see how the political timetables of Mr Erdogan and Mr Putin, who could be in power for another 11 years, will coincide. If it were just a matter of Russia's interests in Syria, then maybe a deal could be worked out. But if Mr Putin's goal is to show how tough he is after more than two decades of geopolitical retreat, and to teach the Americans a lesson about the dangers of allowing the status quo to be upset, then the issue is far more complicated.
The Americans and their allies could always invade Syria, as they did in Iraq and Afghanistan, and Mr Putin's bluff would be called. But there is no sign of that happening. Indeed, Mr Obama, with the support of a war-weary public, is like Mr Putin - unmoved by Syrian bloodshed and suffering.
Turkey, with its new found dynamism, is not a country to be dismissed. The Financial Times this week declared Turkey to be the "true victor" of the Iraq war, having boosted its exports over the past decade by 25 per cent a year. But if there is going to be a deal to end the war it will be between Mr Putin and (he hopes) a humbled America.
More likely, alas, is that the war will continue until finally the Assad regime loses control of the capital.
On Twitter: @aphilps