The reason for Putin's 'escalation' of the conflict concern multiple objectives all tied up with a reassertion of Russia's Great Power status on the regional and global stage. Despite the Obama administration's denials, the differences between the US and Russia over Syria are part of a Great Game of geopolitical chess.
The "moderate" rebels in Syria are, in reality, Sunni jihadist groups backed by America and Britain's Gulf state allies. Some of them, such as al-Nusra, are affiliated to Al Qaida and in conflict with ISIS as the many fragmented 'rebel' groups compete for funding and arms by proving how effective they are against Assad.
The 'extremists' are ISIS because they are not only against Assad but also ranged against the Iraqi Shia dominated government in Baghdad that the US depends upon, along with Iran, to keep Iraq together and prevent it having to re-enter the country militarily after it withdrew combat troops in 2011.
ISIS are also 'extremists' because in 2014 they threatened Erbil and the Kurdish autonomous region and to surge southwards towards Baghdad and Basra: all are major oil producing areas regarded as essential to the present and future supply of oil to the global economy and hence bound up with energy security.
ISIS also poses a threat to Saudi Arabia, especially given its disastrous military intervention in Yemen. This has raised costs to the Saudi state at a time of low oil prices and threatens to destabilise both its finances and ability to use oil revenues to buy off internal discontent. Leading a war against Assad is part of its war against the Shi'ites.
Saudi Arabia has threatened Russia before that it would use jihadists to attack Southern Russia and the Sochi games. It was a terrorist threat that the Western Powers are willing to ignore, partly as France and the US still depend partly on Saudi oil but also due to huge lucrative arms deals with Riyadh.
The other reason Britain ignores Saudi sponsoring of terrorism and an intolerant Wahhabi Islam globally, while claiming to be at the vanguard of fighting terrorism, is that since the 1970s and oil price shock, London has become increasingly a place where Saudi petrodollars have been heavily invested.
There is a clear double standard in condemning Putin for shoring up Assad's state in Syria with arms, air power and military equipment. Britain and the US preceded Putin's move by moving in to support Saudi Arabia's onslaught in Yemen in which Saudi air power has been used indiscriminately to kill civilians.
As regards the absurdity of the Western "public diplomacy" line, Robert Fisk put it accurately when he wrote,
'...within hours of Russia’s air assaults last weekend, Washington, The New York Times, CNN, the poor old BBC and just about every newspaper in the Western world resurrected these ghosts and told us that the Russkies were bombing the brave “moderates” fighting Bashar’s army in Syria – the very “moderates” who, according to the same storyline from the very same sources a few weeks earlier, no longer existed. Our finest commentators and experts – always a dodgy phrase – joined in the same chorus line. 'Putin's move is no mere 'mistake' in his being overzealous to take on ISIS along with the rest of the 'international community' but adding "moderate" groups as targets. Putin aims at wrong footing the western powers tactically by bringing out the contradiction inherent in being against ISIS terrorism but not that of other jihadists.
Groups that were barely mentioned in British newspapers, until Russian fighter jets started bombing them, have suddenly come under the spotlight and are, in fact, not greatly 'less extreme' than ISIS: they are bloodthirsty jihadist movements that still depend upon the Gulf States for finance and weapons.
Western leaders must know this. Yet the underlying geopolitics of energy and influence within the Greater Middle East ensure that the Cameron's sort of moralising drivel about the 'butcher Assad' takes precedence over the fact his opponents are no less ruthless and massacring Alawis and Christians across Syria.
Russia has been able to exploit the absurdity and hypocrisy of Western foreign policy on Syria to lead the way in defending Assad, making the retention of the Syrian state the counterpoint to the sort of chaos unleashed by the West after NATO bombed Gaddafi's forces in 2011 and enabled jihadists to gain ground.
Putin's policy of shadowing Western policy and, in coordinating Russian air power with Assad's forces and Hezbollah on the ground, against 'terrorists' is designed to do three things other that preserve Assad's power base and show Putin as being a strong leader who is effectively 'tough on terror'.
1) Restore Russia as a Global Power that has to be taken into account in the Greater Middle East and as a balancing force to the Western led alliance in the struggle over Syria. By proving Assad is not going to be overthrown, Putin aims at showing that Russia could do a better job of preserving global security against jihadists.
2) Preserve Russia's military presence in the Eastern Mediterranean and its naval base at Tarsous. With the discovery of huge reserves of oil and gas in the Eastern Mediterranean in 2010, Putin wants to position Russia as a power that can protect and be involved in the supply of oil and gas from the region to EU markets.
3) Prevent the possibility of Syria becoming an east-west transit route for Qatari gas pumped from the Persian Gulf towards Turkey and on to EU markets. This would provide a land based energy route that would reduce dependence on Russian gas and hence Russian power in Eastern Europe and Central Asia.
4) Enhance Russia's global standing as a reliable partner in a renewed 'war on terrorism' both in the Middle East, in the Caucasus and Central Asia. When the US started to criticise General Sisi too much after the 2013 coup, Putin was first to try to exploit this to offer Russian technological aid over energy as well as arms deals.
5) Protecting Russia's southern flank against Chechen Jihadists. ISIS has recruited many Chechens spoiling for revenge after Putin crushed the Chechen insurgency in a brutal war which, by the turn of the twenty first century,established Putin as an authoritarian leader who could protect Russia against terrorism.
The presence of Chechens in the jihadist forces surging towards Latakia and towards Russia's military bases would appear to show that they have been able to cross from the Caucasus through Turkey into Syria where they have been deployed as jihadist 'assets' against Assad by Sunni forces there.
One additional factor in the decision to bolster Assad's Alawite dominated home base territory, other than the claim Russia is defending fellow Orthodox Christians too in Syria, is that Russia's SoyuzNefteGas began prospecting for oil in Latakia’s Qenenas district just a week before air strikes started.
6) Countering Georgia's Proxy War. It is thought jihadists from Georgia's Pankisi Gorge have been allowed to spread and recruit by Georgia's security services to be used as assets should Russia threaten the Caucasian state as it did in the 2008 war. Hence the flow of Russian paramilitary forces to Syria.
7) Syria is another front, along with Eastern Ukraine, where Russia is fighting Chechen jihadist paramilitaries to advance its geopolitical reach and wrest control over strategic regions where the Western Powers too are also vying pathologically for access to and control over oil and gas flows between east and west.