BERLIN — As an angry mob stormed the heart of the world’s most powerful democracy, the rest of the world watched the once-unimaginable scenes unfolding in Washington with dismay and disbelief.And many of those following live broadcasts of armed protesters forcing their way into the U.S. Capitol saw a warning for all the world’s democracies: If this can happen in the United States, it can happen anywhere.“We currently witness an attack on the very fundaments of democratic structures and institutions,” said Peter Beyer, the German government’s coordinator for trans-Atlantic affairs, who was watching the scenes from Washington live on TV. “This is not merely a U.S. national issue, but it shakes the world, at least all democracies.”As shocking as the violence on Wednesday was, some were not totally surprised that the Trump presidency was ending like this, in a spasm of chaos.ImageThe mob climbing the Senate side of the Capitol.Credit...Jason Andrew for The New York Times“This is what happens when you sow hatred,” Stéphane Séjourné, a member of the European Parliament and close ally of President Emmanuel Macron of France, wrote on Twitter. “Let us defend and protect our democracy, because it cannot be taken for granted.”Several leaders directly blamed President Trump for the violence.“The peaceful transfer of power is the cornerstone of every democracy. A lesson once taught to the world by the USA,” the German vice-chancellor, Olaf Scholz, wrote. “It is a disgrace that Donald Trump is undermining it by inciting violence and destruction.”Jeremy Hunt, a Conservative former foreign secretary in the United Kingdom, said on Twitter that Mr. Trump “shames American democracy tonight & causes its friends anguish but he is not America.”ImageIn the Capitol on Wednesday.Credit...Erin Schaff/The New York TimesEven the Secretary General of NATO took the unusual step of weighing in on a domestic issue in a member state. “Shocking scenes in Washington, D.C.,” Jens Stoltenberg wrote in a tweet. “The outcome of this democratic election must be respected.”For many foreign leaders, the scenes in America also conjured uneasy echoes of recent attacks on democracy at home.Heiko Maas, the German foreign minister drew a parallel between the storming of the Capitol and the recent attempt by a mob of far-right German protesters to enter the Reichstag, the building that houses Germany’s Parliament.“Inflammatory words will lead to acts of violence — on the steps of the Reichstag, and now in the Capitol,” Mr. Mass wrote on Twitter. “The contempt for democratic institutions has a devastating effect.”“The enemies of democracy will be happy about these unbelievable pictures from Washington D.C.,” Mr. Mass added.ImageU.S. Capitol police with guns drawn guarding a barricaded door as the mob tried to break into the House chamber.Credit...Andrew Harnik/Associated PressAnd they were.In Russia, the violence fit neatly into the Kremlin’s propaganda narrative of a crumbling American democr