On the morning of September 10, Nato jets were scrambled over eastern Poland to defend the airspace of an alliance member against an incursion by Russian drones. It was the first time that the west fired shots in the Kremlin’s war against Ukraine.

This incursion marks a serious escalation by Moscow. But it also highlights yet again that the west has no clear red lines and is unprepared to respond decisively if red lines that were taken for granted in the past – like the territorial integrity of Nato members – are crossed.

This latest Russian escalation isn’t the usual war of words. It was only last week that Russia’s president, Vladimir Putin, warned that foreign troops in Ukraine would be legitimate targets for his invasion force.

He slightly qualified his comments by noting that this would be the case “especially now, while the fighting is ongoing”. But the message was nevertheless clear. Russia will oppose any international security guarantees that involve western troops in Ukraine. This has been a long-standing and frequently articulated position by Russia. Yet, Putin’s rhetoric threatening to target western troops clearly ups the ante.

But these are not the only ways in which the Kremlin has markedly turned up the pressure over the past few weeks and months. Russia has also retained some momentum in its military campaign in Ukraine and has been further empowered by several successes on the diplomatic front.

On the battlefield, Russia has continued to demonstrate significant advantages in manpower and military hardware.

Where the entire Nato alliance struggled to cope with the incursion of just 19 drones, Ukraine has been subject to an intense........

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