CLAUSEWITZ may not quite have said that war is the continuation of politics by other means, but the essential truth of that observation remains.

War is always political, never more so than today as we stand on the brink of what could be a confrontation with Russia on a global scale – a world war by other means. Wars happen when weak politicians back themselves into a corner, and world wars start when they honour unthinking political alliances.

The Syrian civil war is the front line of a complex proxy war between not just the US and Russia, but Iran and Saudi Arabia, with a side order of Israel, which is always looking for an opportunity to strike at Hezbollah, as we saw on Monday in Homs. There is already a low-intensity war with Russia in Europe – in the Ukraine, which has been festering since Russia annexed Crimea in 2014. Nato has been bolstering its military front line by incorporating the Baltic states and a slew of former Eastern bloc countries bordering on Russia. Vladimir Putin, meanwhile, is trying to compensate for Russia’s strategic weakness by exploiting new opportunities in cyber warfare. (And, whisper it, we are doing exactly the same).

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This is a dangerous world, and it just got a lot more dangerous with the sabre-rattling at Russia over Douma. There is much lamentation in the wake of the latest alleged chemical attack on civilians by President Assad about Britain’s failure to act. “Russia is getting away with murder in the Middle East. We must do something” – but we are doing something. Tornado jets started bombing raids in Syria in 2015, and British special forces are also in operation there – one of them was killed last month. Putting further British boots on the ground in Syria now would be madness.

Tony Blair warned yesterday about the “consequences of NOT intervening in Syria”. Yet, he is living proof of the dangers of starting land wars in the Middle East with simple-minded objectives. It’s all very well fantasising about ”taking out Assad”, in the way he and George W Bush sought to take out Saddam – that was disastrous enough for the Middle East. Direct involvement in this cat’s cradle of toxic alliances could have untold consequences for the world. Unlike the relatively stable and binary Cold War, it would be a war on many fronts and many dimensions – and once begun it would be almost impossible to stop. Indeed, it may already have started.

Political leaders are weak and war talk is seductive – a useful distraction from domestic political difficulties. Over the past decade, Vladimir Putin has systematically used military confrontation to leverage Russian, and his own, status on the world stage. Russia may have the GDP of a a middle-ranking American state, but by throwing his weight around in Syria and Crimea, he has become hugely popular at home. Mr Putin has deftly exploited collective memories of the Soviet era to suggest that his country has been bullied by Nato. Unfortunately we’ve contributed to his myth-making by resorting to Cold War rhetoric and by recklessly encroaching on the Russian homeland.

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But it’s not just Mr Putin who benefits from a climate of rising tension. Theresa May has been boosted by her response to the poisoning in Salisbury of the former Russian double-agent Sergei Skripal and his daughter, who has staged a miraculous recovery. I’m not accusing the PM of exploiting this atrocity for personal political gain, nor do I subscribe to the conspiracy theory that it was a covert operation by Western intelligence to discredit Russia. But it would be naïve not to observe how effective this crisis has been for a Prime Minister who only a few weeks ago was being written off, even by Conservative commentators, as a hopeless, indecisive “Maybot”.

Similarly, an easy war would work wonders for Donald Trump, an embattled President, mired in sordid sex scandals, who risks being impeached because of his election campaign’s alleged contacts with, er, Mr Putin’s Russia. That is all being set aside as as the political world hangs on his promises of military retaliation for the deaths of “beautiful babies” in Khan Sheikhoun last year and Douma this week. Anyone who demurs, or urges caution, still less asks for firm evidence of chemical weapons in Douma, is accused of being an apologist for Mr Assad or Mr Putin.

That is precisely the charge levelled against the former British Ambassador to Syria, Peter Ford, who argued passionately on BBC’s Good Morning Scotland yesterday against plunging into a war over what could be an act of provocation. Mr Ford says that the White Helmets, the volunteer group who provided most of the evidence for the chemical attack, are unreliable sources and easily capable of staging a “false flag” event. The Syrian government is on the point of winning its war against the rebels, he says, so why would it provoke international intervention at this point?

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Well, perhaps because it can. We shouldn’t be naïve about the calumny of the Assad regime, but nor should war be conducted on the basis of hearsay alone. The Assad regime is probably responsible for the Douma attack – it certainly used chemical weapons before in 2013 in Ghouta, but no one has the proof. Further action, military or political, should only come after a process of verification by the Organisation for the Prohibition of Chemical Weapons and due process. As we saw in Salisbury, rushing to judgment is silly and counterproductive. Any escalation in Syria would have to be with a very clear and achievable objective, not as an emotional response to TV images.

Against the background of a global economy that has never fully recovered from the financial crash, and with raging discontent and paranoia fuelled by social media, the world is, as Mr Ford warns, only a few steps away from a catastrophic accident. Politicians get carried away with their own rhetoric and weak leaders are often the most prone to military adventurism. That is because they are loathe to tell voters the sober reality that, very often, doing something is worse than doing nothing at all.