The USS Porter guided-missile destroyer is seen launching Tomahawk cruise missiles at Syria's Shayrat

The US strike against Syria’s Shayrat airbase earlier this month – prompted by a sarin attack on the rebel-held town of Khan Sheikhoun days before – was limited in scope. But it heralded an about-turn in the Trump administration’s thinking: In a matter of days, a government that had previously wanted little to do with the Syrian war was now saying regime change in the country was a priority and that any additional use of chemical weapons by president Bashar Al Assad’s government would be met with a devastating response.
But the window for a future "easy" intervention in Syria may have just passed.
On Wednesday, CNN reported that – according to US defence officials – Damascus had relocated most, if not all, of its operational combat aircraft to Basel Al Assad International Airport in Latakia province, western Syria, which shares facilities with Russia’s Hmeimim airbase, including runways.
The base, Russia’s most important in Syria, sits directly next to the airport’s terminal building at the northern end of its runways. Even if Syrian planes are not parked in Russian-controlled areas, any strike on them could endanger Russian lives and equipment due to their proximity.
If the United States wants to strike at the Syrian air force now, it will have to do so in an area where the Russians are more the hosts rather than guests. This raises the stakes dramatically: Any attack on Syrian planes at the Basel Al Assad airport could be perceived as an attack on Russia.
There are, of course, other military targets in Syria that Washington could hit. But if the US ever wants to seriously push regime change in Syria then taking Mr Al Assad’s planes out of the sky will be central to its mission. Syria’s air force would also inevitably be the chief target of any US strike responding to another chemical weapons attack launched from the air.
It was the Syrian air force that Washington went after on April 7 when it fired 59 Tomahawk cruise missiles into the Shayrat airbase near the western city of Homs, claiming afterwards to have taken out a fifth of the operational aircraft. Russian forces were stationed at Shayrat too, but the US gave Moscow advance warning of the strike to avoid collateral damage. Even if given a similar warning, it is unlikely that Russian forces would willingly vacate Hmeimim – a base Moscow has leased from the Syrian government and considers to be its own.
By relocating its aircraft, Damascus is banking on Washington’s reluctance to risk a larger conflict with Moscow over Syria. And it is also signalling how seriously it takes Washington’s threats of further action.
But although the move could shield the Syrian air force it also potentially poses a dilemma for Russia.
If Damascus chooses to ignore America’s warnings about using chemical weapons, it will be much harder for Moscow to claim ignorance when it controls the base which is now to be the launch pad for any future Syrian air strikes, including chemical attacks.
So far Russia has stood by Damascus in denying Syria had any responsibility for the April 4 sarin attack, that prompted the US strike on Shayrat. At first Moscow said a "terrorist" chemical weapons warehouse had been hit and later suggested the sarin attack may have been a false flag attack designed by Syria’s enemies.
But amid the vocal support for the Assad regime, the Kremlin has also made it clear that is not unconditional. And Moscow will be judged even more culpable if the Syrian government perpetrates more atrocities via jets launched from a Russian airbase.
Moscow’s unwavering support for Damascus has left Russia open to even more condemnation from the international community and further committed it to an intervention that, according to president Vladimir Putin earlier this year, was supposed to be close to ending.
And if shifting Syria’s air force deters further US action, Damascus will be even more indebted to its Russian allies.

Source: The National