"It's certainly one way of focusing our minds — and wallets! Donald Trump is doing us a favour, if we choose to think about it that way. And we may as well look on the bright side. Otherwise these times are too dark."

The words of a diplomat from a major European country, speaking after Donald Trump turned off the military aid tap to Ukraine on Monday. He asked not to be named, so he can share his thoughts more freely.

The relentlessness, and pace, of change in Washington, can be dizzying. Not only for consumers of news but politicians as well.

Europe is scrambling to react effectively.

There has been a frenzy of diplomatic activity: bilateral, late-night leader phone calls, European huddles in London and in Paris, meetings of Nato defence ministers in Brussels. An emergency security summit of EU leaders is also scheduled this Thursday.

It is a huge moment in European history.

Most European countries believe the security of all of Europe, not only the sovereignty of Ukraine, is at stake — with Russia looking to dismantle the western-facing balance of power, in place since the end of the Cold War.

Washington, which has had Europe's back in terms of security and defence since World War Two, now appears "not to care about the fate of Europe", according to the man poised to be the next leader of the continent's biggest economy, Friedrich Merz of Germany.

But what are all the big-name European meetings and summits actually achieving?

Just a few hours prior to Washington halting military aid to Kyiv, UK Prime Minister Sir Keir Starmer, who is taking a lead in Europe over Ukraine, announced it was time for "action not words". The European Commission President Ursula von der Leyen, meanwhile, said Europe must turn Ukraine into a "steel porcupine", with urgent, extra arms deliveries.

Can the continent really act as one, though? Europe is a sum total of different countries with different-sized budgets and diverse domestic politics and priorities.

Europe's aim in taking this defence action is two-fold:

First, to show Donald Trump that — in the words of the UK prime minister........

© BBC