Donald Trump appears to have had a major change of heart with regard to Ukraine. On the face of it, it looks like he has embraced outright optimism that Kyiv "is in a position to fight and WIN all of Ukraine back in its original form."

This came with the message that Europeans will need to be in the driver's seat to make this happen. According to Trump, a Ukrainian victory depends on "time, patience, and the financial support of Europe and, in particular, NATO."

The only US commitment is "to supply weapons to NATO for NATO to do what they want with them." Most tellingly, Trump signed off from his Truth Social missive with: "Good luck to all!" This is perhaps the clearest indication yet that the US president is walking away from his efforts to strike a peace deal.

It also suggests that he has given up on a separate deal with his Russian counterpart, Vladimir Putin. But this is where the good news ends – and where the European-led coalition of the willing will need to deliver security and stability for the continent in an ever more volatile environment.

After several weeks of Russian incursions into NATO airspace, drones – thought highly likely to be linked to Russia – twice disrupted Danish airspace in the vicinity of Copenhagen airport. It felt like a presentiment of the dystopian drone wars predicted by Ukrainian President Volodymyr Zelensky in his speech at the UN general assembly in New York on September 24.

Putin's continuing provocations are a brazen challenge to Kyiv's European allies. At the heart of this coalition of the willing, the European Union certainly has demonstrated it is willing to flex its rhetorical muscles to rise to this challenge.

EU institutions in Brussels have never left any doubt about their determination that Russia's war of aggression against Ukraine "needs to end with a just and lasting peace for Ukraine", as Ursula von der Leyen, the EU commission president, put it most recently in her state-of-the-union address.

Beyond rhetoric, however, the coalition of the willing is facing a number of potential problems. Individually, none of them is insurmountable, but taken together they illustrate the unprecedented challenge Kyiv's European allies are facing.