 After a decade of testing the boundaries of political speech in Germany, Mr. Hacke, a leader of the Alternative for Germany party or AfD, no longer needed to push the limits himself, the crowd did it for him. That moment crystallizes why, to his critics, Mr. Hacke is not simply a challenge to the political order, but a threat to German democracy itself. Everything for Germany, alles für Deutschland, was the slogan engraved on the knives of the German SA stormtroopers.