During the Cold War, there was a consensus amongst western leaders never to speculate about the circumstances in which they would deploy nuclear weapons. In that situation, strategic ambiguity worked.

Today's debate in Europe about the circumstances of when to send ground troops to Ukraine could not be more different. Emmanuel Macron raised the issue on a couple of recent occasions when he said circumstances might arise that might justify the dispatch of ground troops. In a swipe directed against Olaf Scholz, he said you should never signal your red lines to an opponent who has made it a habit to cross lines.

I agree with Macron, but his version of strategic ambiguity is not working because it only reveals Europe's divisions. Franco-German unity is not a sufficient, but a necessary condition for Europe to exert any power. Scholz spoke out against ground troops. So did Donald Tusk, the Polish prime minister. By contrast, his foreign minister, Radoslaw Sikorski, appeared to side with Macron. The reality is that the EU is all over the place on this question. And that's the message we are sending to Vladimir Putin.

The problem with the western alliance on Ukraine is a combination of US reluctance, German red lines and French grandstanding. The US House of Representatives is still withholding the funds for Ukrainian aid, and there is no end in sight to the blockade. During the first two years of the war, the US was Ukraine's biggest supporter by far. I cannot see the House Republicans releasing the funds now that Donald Trump is the only Republican candidate left.

French support for Ukraine comes mostly in the form of rhetoric - as opposed to direct financial and military assistance. Measured in terms of gross domestic product, France ranks number 28 amongst Ukraine's supporters. 

Germany is a much bigger supporter of Ukraine, both financially and militarily. And yet Scholz has managed to look like the bad guy. Ground troops are indeed a red line for the German chancellor. He also opposes the dispatch of Taurus cruise missiles, fearing that Ukraine might use them to hit targets in Russia. Current polls would suggest that he will not get a second term. But with his opposition to the delivery of offensive weapons, Scholz is tapping into an underlying unease about the war.

Friedrich Merz, the German opposition leader, is much more forthright in his support for Ukraine, especially on the question of whether to send Taurus missiles. But the big unanswered question for Merz and other European leaders is what they would do if a Trump-led US were to withhold support. Would Merz really take on a leadership role? Would Macron turn over his seat at the UN Security Council and offer his nuclear arsenal to the EU? Of course not. Most likely, the Germans will revert to the old reflex of carving out deals with Euroasian dictators favourable for German industry. The worse their economy performs, the greater the temptation will be. And Macron will continue to excel at grand speeches. There will be some measurable progress in Europe, on defence procurement for example. But it is too late to influence the outcome of the Ukraine war.

Where I can see a narrow leadership role for Macron is in the protection of Moldova. He spoke about the deployment of western troops in case of a Russian advance on Odessa. The Black Sea port city is only a few kilometres away from the border with Moldova. A Russian invasion of Moldova would indeed constitute a scenario that would threaten the security interests of the EU and Nato in a massive way. Macron and Maia Sandu, the Moldovan president, last week agreed a defence pact as part of which France would guarantee the country's security. France has historically played a strong role in this region. It would be a strategic disaster for the world if Putin controlled the entire Black Sea. And the task of defending a small country like Moldova is a much more realistic order of magnitude than the liberation of 160,000 square kilometres of Ukrainian territory currently occupied by Russia. It is just not credible that the west sends troops to the Donbass, and fights a hot war with Russia. But it can protect Moldova.

The west could also help Ukraine defend itself against further Russian advances. But even this modest, and some would say disappointing, war goal would require a lot more money and military support than Europe is currently providing. While it may be hard for Macron to co-opt Scholz into such a project, I believe it is at least possible for Germany under a different leadership to align behind a strategy that is focused on an outcome that is at least militarily achievable.

Macron's latest intervention goes right to the core of my criticism of the western response to Russia's invasion. It is not about whether it is right or wrong to help Ukraine. Of course, it is right. It is about persistent misjudgements, hypocrisy, and amateurism. The west has misjudged the economic impact of sanctions, and in some cases, its own electorate. The west is hypocritical with the declaration of war goals that stand in no relationship with the levels of support.

A professional poker player would not discuss bluffing strategies while playing a game, and probably not even afterwards. Amateurs, by contrast, always boast about their skills. Sikorski's comment that strategic ambiguity would make Putin afraid has the quality of an amateur's bluff.

Strategic ambiguity is a good idea in principle, but with unity it is meaningless. The reality is that nobody is afraid of us, least of all Putin.