At a gathering in Madrid, members of Europe’s far-right parties set aside any trepidation they might have about President Trump’s threats, and instead focused on a common enemy — the European Union. ...There was Marine Le Pen of France’s far-right National Rally; the Netherland’s populist, Geert Wilders; the leader of Italy’s League party, Matteo Salvini. All made clear that they shared Mr. Trump’s charge against what they see as “wokeism,” “gender theory,” and overweening environmentalism. For them, the American president had blown through the last barriers that had confined their parties to the political margins. The taboos had been toppled....