The rise of arch-isolationist JD Vance has cemented Europe’s fears that a second Trump presidency would drastically reduce transatlantic security ties and sever critical US support for Ukraine’s defence against Russian aggression.

Donald Trump’s selection of Vance as his running mate on Monday night intensifies long-running concerns among US allies that the Republican candidate for November’s election intends to run a protectionist “America first” administration, with huge implications for Europe’s defence and economic security.

“More champagne popping in the Kremlin,” said Guy Verhofstadt, a member of the European parliament and former Belgian prime minister, in response to Vance’s nomination, in a post on X. “Are Europe and UK preparing yet or still shuffling the deckchairs on the Titanic?”