It is easy to forget that besides Paris, a city many of us know and like as a city of culture, Russia has been attacked by Daesh/Isis. The group is a threat to the whole world and is seeking to impose its ideology on all countries, starting with the Middle East.
Two hundred and twenty four people died when a Russian charter flight was brought down over Sinai by a bomb; that is more than the fatalities in Paris (129) and London's 7/7 attacks (52) combined.
Our choice of allies is limited. As Winston Churchill, the UK's greatest modern wartime leader, said of his pact with Stalin: "If Hitler invaded hell I would make at least a favourable reference to the devil in the House of Commons." I suspect he might think the same of Vladimir Putin, and even Assad.
After the war was won, with the loss of approximately 26m Russians, there was a Cold War which the West won. Churchill and Roosevelt, the US President, knew that it was better to deal with Russia later than lose. It would have been worse still to have let him destroy Russia and conquer continental Europe, not to mention completing his genocide against Jews, gypsies, homosexuals and the disabled.
Hitler, or his successor, would have been far harder to deal with after that. His entire policy was based on conquest, revenge and a distorted sense of mission. You could say the same about Daesh, which is, by the way, a name that Isis hates. It means "a bigot who imposes his view on others,'" and Daesh threatens to cut out the tongue of anyone who uses the word.
They want a worldwide caliphate to surpass the medieval Muslim conquests. That territory stretched from Spain, across North Africa, to well beyond the Caspian Sea. Non-Muslims would be forced to pay a penal tax of up to 50%, convert or die.
Cultural artefacts and religious images would be destroyed, as they are in Syria, to wipe out the memory of European civilisation.
The original Muslim conquest had many faces, as all great empires have many faces. Andalusia in Spain declined economically and agriculturally when they were driven out. The great buildings the Moors constructed are still a source of pride, and considerable tourist revenue, to Spain.
Daesh won't rival those achievements. The hallmark of territories they or the Taliban control has been destitution, public execution and mutilation. That is before you start on freedom of conscience and the suppression of women.
They want to get control of oil wells to fund their war effort, which means extensive conquest and instability in the Middle East. If they get near Israel it could provoke an atomic response, and if Daesh reaches Pakistan, they would have a bomb too.
We in the West could see how it goes. We would be faced with a dilemma, and the longer we stand on the sidelines, the harder it becomes to respond effectively.
Yet, however hard we try, what we can't do is bomb them out of existence. Campaigns against a state-like entity like Daesh are only defeated by ground troops. That is too rich for the West's blood just now.
If we want to fight, and not stand back, we need someone else's ground troops to do the dirty work. That is what happened in Afghanistan, where an unsavoury bunch called the Northern Alliance were used to take Kabul. So far, the Kurds have been the only reliable ones we have found.
The Stalin in this scenario is Bashir al Assad, the beleaguered dictator. He controls territory including all the ports.
Many of the refugees are from the middle class who grew up under his rule. Besides, he is allied with Putin and can hold out with his help, as well as that of France.
What the west needs, and has never had, is a realistic strategy. That involves getting rid of Daesh first and then a programme for elections in Syria once the conflict is over.
In the meantime, throwing money at 'good' rebel fighters is a risk. We don't really know who they are or where aid ends up.