President Volodymyr Zelensky knows how to get us. He invoked Churchill to the Brits, Pearl Harbour to the Americans, and told the Germans that they once made a promise: “never again”.

He did not get Olaf Scholz, though. The German chancellor did not want to be lectured by a political rock star. I have sympathies for Scholz. Russia’s attack on Ukraine requires some cold-blooded strategic thinking on the part of the west, rather than the cheerleading that is happening in the media and social networks right now.

It is not for us to give Zelensky advice on what he should do on the ground, and at what point he should cut a deal. Instead, what we in the west should do is be clearer about what we can do. For example, we can't fast-track his country’s membership application for the EU. It is really quite dangerous to dangle this carrot in front of the Ukrainians at a time like this. France has been blocking North Macedonia and Albania's accessions. There is no way that the EU can fast-track Ukraine without fast-tracking the others.

Several rounds of EU enlargement, without accompanying deepening, have left it in an unbalanced position. Advocacy for EU enlargement has been and remains loudest amongst British journalists and academics. What they don’t seem to realise is that Brexit really shifted the debate on enlargement. Also consider that if the EU were to develop into a defence union, would we not risk direct conflict with Moscow over Ukraine another time?

Another carrot we are dangling in front of the Ukrainians is weapons. Most of the German weapons that were promised never arrived. Future weapons deliveries are going to get harder because Nato does not want to confront the Russian military directly. Sergei Lavrov, the Russian foreign minister, said that western arms convoys constitute a legitimate target in the war. We should expect western weapons supplies to Ukraine to dry up over time.

A stick that the Ukrainians are holding over our heads is the repeated assertion that after Putin takes Ukraine, we are next. I understand why he wants to spin that narrative. But it is not true. Putin’s radius of horror is limited to the Russo-sphere that is not in Nato: Ukraine, Georgia, maybe Moldova. Nato’s response to this war has surprised him, and it will be stationing an overwhelming number of troops and weapons on its eastern front. Invading a Nato country would be too risky, even for a man who takes calculated risks.

Putin can, however, win the war in Ukraine because he has the deadliest weapons, and is willing to target civilians. Once the western weapons supplies end, the odds in this war will once again favour Russia. Time is on Putin’s side.

He can also rely on our short attention spans. The British tabloids are already starting to lose interest. The media and Twitter are once again obsessing over gaffes from Boris Johnson, and other grave matters of state. Will we still see pictures from Ukraine at the top of news broadcasts in four weeks' time? In four months' time? Is it possible that Putin waits until we are distracted before he unleashes his deadliest weapons? The west did not care all that much about cluster bombs in Aleppo.

Europe can, and should, make a credible promise that we will welcome Ukrainian refugees in the millions. But our ability to help Ukraine win the war is limited. This is what we must tell Zelensky. The cheerleading has to stop.