It's a meeting to chart a future for Syria, featuring the major players involved in the country's brutal seven years of war.
But the United States will not be there.
Russian President Vladimir Putin will sit down with Turkish President Recep Tayyip Erdogan and Iranian President Hassan Rohani on April 4 in Ankara for the highest-level talks on Syria's future in five months.
The problem is that, more often than not, Russia, Turkey, and Iran have shown conflicting priorities and divergent interests both for Syria and the entire region.
That, many veteran observers and experts say, means the meeting could end up being more an exercise in public relations rather than substantive policy decisions.
"It's not clear to me what they can agree upon," said Mark Katz, a Middle East scholar at George Mason University, in Virginia. "I think for these guys the optics will be good enough."
All three countries have their own agendas in Syria.
Tehran has long supported the regime of President Bashar al-Assad and the Shi'a Alawite base that he draws support from, but it is also a foe of NATO ally Turkey.
Moscow has supported Iran economically, including some of its nuclear programs, and Syria is Moscow's closest ally in the Middle East.
Turkey opposes Assad, and has clashed on and off with Russia for centuries.
"From the beginning, this triangular alliance between Moscow, Ankara, and Tehran, is an alliance of convenience," said Marc Pierini, a former European Union ambassador to Turkey, Syria, Libya, and Tunisia."It is very unusual because of the divergent interests [they have]."
Then there is Washington -- long a dominant force in Middle East politics -- with which all three countries have conflicting agendas.
Iran is a decades-old enemy and fiery rhetoric has increased between Tehran and the United States since Donald Trump became president. Turkey is a NATO ally with currently tense relations with Washington, particularly over U.S. support of Kurdish militias fighting in Syria. And Russia views the United States much as the Soviet Union did: a geopolitical rival who should be thwarted wherever and whenever possible -- bilateral relations recently described by Russian Foreign Minister Sergei Lavrov as "worse than during the Cold War."
Yet all three simultaneously need some sort of U.S. presence to balance out countervailing forces: for example, to restrain Israel from taking more aggressive action against Syrian government forces and Iranian proxy militias. Or to help organize and fund a reconstruction effort in Syria once the conflict finally ends.
"For the moment it makes it look like they're the ones all making the decisions and, of course, without the United States. And they all like that idea, they're making policy independent of the United States, that is their own basic common denominator," Katz said.
Then there is the fact that each wants to keep one or the other off balance: Turkey wants to keep Iran at bay but wants to see Assad go; Russia wants closer ties with Turkey but also needs Syria for its Mediterranean naval base in Tartus; Iran wants to maintain supply lines to Hizballah in Lebanon and keep Turkey from moving into Iraq.
"They're certainly not going to tell one another what's really on their minds," said Patrick Clawson, director of research at the Washington Institute for Near East Policy. "It will be a consequential meeting, but one fraught with a lot of differences."
The last meeting between Putin, Rohani, and Erdogan took place in November, in the Black Sea resort of Sochi.
Dubbed the Astana Process -- after the Kazakh capital city where the three countries first started a joint effort -- that meeting, and the ones that preceded it accomplished little, and in the months that followed there was increased military action in Syria by all three and their proxies.
Syria, meanwhile, has continued to conduct chemical weapons attacks on opposition forces in civilian areas, despite global condemnation.
"Nobody in the West believes that the Astana Process will produce a lasting result, so it will have to go back to the UN tables in Geneva, and to have a fruitful discussion there you need a solid, consistent position from the U.S. and a solid position from the U.S.-European perspective, which isn't there," said Pierini, who is a scholar at Carnegie Europe.
Meanwhile, Turkey's actions and its warmer ties with Moscow, Pierini continued, appeared motivated in part by domestic politics and nationalist politicians who consider the Kurds to be a threat to the Turkish state.
"The real risk for the West...is that both Iran and Russia might give a green light to Turkey to extend its operations into eastern Syria, east to the Euphrates [River], all the way to the Tigris [River]," Pierini said, where there are some 2,000 U.S. forces operating along with British and French units, and Kurdish militias.
"That would be immensely complicated," he said.
Where Russia is concerned, its actions in Syria have long been part of a strategy aimed at standing up to the United States for major geopolitical crises, veteran Russian analyst Olga Oliker said. But that poses risks for Moscow.
"Russia's approach seemed to be this: stand up to the United States, let's say in Syria, then make a deal, and then it is a shared responsibility. But now Russia is facing the model: Russia stands up to the United States -- again, let's say in Syria -- the United States flails, and Russia is left holding the bag on Syria," she said in a conversation last month at the Wilson Center's Kennan Institute in Washington.
"Russia is left to figure out the end game, with the United States to some extent playing the role of the spoiler. It is a reversal of roles!" she said.
Steven Cook, an expert at the U.S.-based Council on Foreign Relations who focuses on Arab and Turkish politics, said that, as much as anything, the Ankara meeting is a reminder of Russia's success in moving into the vacuum left by the United States' disengagement in the region.
"In Syria, the Russians have demonstrated political will and staying power," he wrote in an analysis this week. "This is more important than, for example, the size of Russia's economy, which has been used as an indicator of Moscow's weakness."
"The Russians are not going away, they have a strategy to weaken the West, and it starts in the Middle East. Moreover, Moscow no longer has the ideological baggage of communism, making it easier for it to make inroads in the region," he concluded.