US could dent Russian and Iranian influence in region

For Iran, Syria is the key, the central theatre of a war for regional hegemony

The US shoots down a Syrian fighter-bomber. Iran launches missiles into eastern Syria. Russia threatens to attack coalition aircraft west of the Euphrates. What is going on?
It might appear a mindless mess, but the outlines are clear. The great civil war, centered in Syria, is approaching its post-Daesh phase. It's the end of the beginning. The parties are maneuvering to shape what comes next.
It's Europe, 1945, when the war was still raging against Nazi Germany, but everyone already knew the outcome. The maneuvering was largely between the approaching victors - the Soviet Union and the Western democracies - to determine postwar boundaries and spheres of influence.
So it is today in Syria. Everyone knows that Daesh is finished. Not that it will disappear as an ideology, insurgency and source of continuing terrorism both in the region and the West. But it will disappear as an independent, organised, territorial entity in the heart of the Middle East.
It is being squeezed out of existence. Its hold on Mosul, its last major redoubt in Iraq, is nearly gone. Raqqa, its stronghold in Syria and de facto capital, is next. When it falls - it is already surrounded on three sides - the caliphate dies.
Much of the fighting today is about who inherits. Take the Syrian jet the US shot down. It had been attacking a pro-Western Kurdish and Arab force (the Syrian Democratic Forces) not far from Daesh territory.
Why? Because the Bashar Assad regime, backed by Iran, Hezbollah and Russia, having gained the upper hand on the non-extremist rebels in the Syrian heartland (most notably in Aleppo), feels secure enough to set its sights on eastern Syria. If it hopes to restore its authority over the whole country, it will need to control Raqqa and surrounding Daesh areas. But the forces near Raqqa are pro-Western and anti-regime. Hence the Syrian fighter-bomber attack.
Hence the US shoot-down. We are protecting our friends. Hence the Russian threats to now target US planes. The Russians are protecting their friends.
On the same day as the shoot-down, Iran launched six surface-to-surface missiles into Syrian territory controlled by Daesh. Why? Ostensibly to punish the militants for terrorist attacks two weeks ago inside Iran.
Perhaps. But one obvious objective was to demonstrate to Saudi Arabia and the other Sunni Arabs the considerable reach of both Iran's arms and territorial ambitions.
For Iran, Syria is the key, the central theatre of a war for regional hegemony.
Iran (which is non-Arab) leads the Shia side, attended by its Arab auxiliaries - Hezbollah in Lebanon, the Shia militias in Iraq and the highly penetrated government of Iraq, and Assad's Alawite regime. (Alawites being a non-Sunni sect, often associated with the Shias.)
Taken together, they comprise a vast arc - stretching from Iran through Iraq, Syria and Lebanon to the Mediterranean. If consolidated, it gives the Persians a Mediterranean reach they have not had in 2,300 years.
This alliance operates under the patronage and protection of Russia, which supplies the Iranian-allied side with cash, weapons and, since 2015, air cover from its new bases in Syria.
Arrayed on the other side of the great civil war are the Sunnis, moderate and Western-allied, led by Saudi Arabia, the Gulf states, Egypt and Jordan - with their Great Power patron, the United States, now (post-Obama) back in action.
At stake is consolidation of the Shia Crescent. It's already underway. As Daesh is driven out of Mosul, Iranian-controlled militias are taking over crucial roads and other strategic assets in western Iraq. Next target: eastern Syria (Raqqa and environs).
Imagine the scenario: a unified Syria under Assad, the ever more pliant client of Iran and Russia; Hezbollah, tip of the Iranian spear, dominant in Lebanon; Iran, the regional arbiter; and Russia, with its Syrian bases, the outside hegemon.
Our preferred outcome is radically different: a loosely federated Syria, partitioned and cantonised, in which Assad might be left in charge of an Alawite rump.
The Iranian-Russian strategy is a nightmare for the entire Middle East. And for the US too. The Pentagon seems bent on preventing it. Hence the Tomahawk attack for crossing the chemical red line. Hence the recent fighter-bomber shoot-down.
A reasonable US strategy, given the alternatives. But not without risk. Which is why we need a national debate before we commit too deeply. Perhaps we might squeeze one in amid the national obsession with every James Comey memo-to-self?
- The Washington Post Writers Group

• MENA