During his election campaign, President-elect Donald Trump faced any number of comparisons with Adolf Hitler. On Wednesday, he decided it was his turn to make a Nazi reference.

On Twitter, Trump accused the U.S. intelligence community of leaking information on compromising details that Russia had allegedly gathered about him. “Are we living in Nazi Germany?” he asked.

The answer is no, as Germans quickly confirmed to Trump on the social network. Despite criticism, Trump later Wednesday repeated and attempted to explain the Nazi Germany reference during a news conference, his first since July. The president-elect said it was “disgraceful that intelligence agencies let out any information that turned out to be so false and fake” and again claimed this was “something Nazi Germany would have done.”

Comparisons to Hitler and Nazi Germany aren't usually good ones for politicians to make, at least from a historical angle. Particularly in Europe, such claims have often turned into an embarrassment and caused diplomatic as well as political damage.

In 1985, former German chancellor Willy Brandt of the Social Democratic Party faced strong criticism for calling the secretary-general of the rival Christian Democrats “the worst agitator since Goebbels.”

It was a particularly harsh Nazi comparison; Joseph Goebbels was Hitler's propaganda minister and one of the key strategists behind the horrors the Nazis inflicted upon Europe. Amid continuous criticism of his rhetoric, Brandt later said his comments were “unnecessarily pointed.”

The remarks of one of his successors, Chancellor Helmut Kohl, temporarily put relations between the Soviet Union and West Germany on ice. In 1986, just three years before the fall of the Berlin Wall, Kohl compared then-Soviet leader Mikhail Gorbachev to Goebbels as well.

The interview was published in Newsweek, but Kohl rushed to distance himself from his own words amid the looming diplomatic crisis. Kohl first apologized in writing, then gave a parliamentary speech in which he claimed that the magazine had twisted his words.

His apologies didn't go over well. The Soviet Union temporarily cut off diplomatic relations with West Germany and expressed “deep indignation.” It took two years for the two countries to reestablish relations.

In 2002, four years after Kohl left office, then-Justice Secretary Herta Däubler-Gmelin was forced out of the German cabinet for comparing George W. Bush to Hitler because of Bush's plans to go to war in Iraq. “Bush wants to divert attention from his domestic problems. . . . It’s a classic tactic. It’s one that Hitler also used,” Däubler-Gmelin said in the controversial interview published by a local German newspaper.

According to historians familiar with those scandals, there are multiple reasons why Hitler comparisons are rarely taken lightly in contemporary Germany — and should be treated similarly elsewhere.

“For Germans Adolf Hitler is the symbol for all the crimes their country has committed,” German historian Thomas Weber explained last year. Weber, a professor at the University of Aberdeen in Scotland, has researched Hitler and Germany's Nazi past for years and has written numerous books on the issue. According to Weber, the common thinking in Germany is simply that “nobody can ever be as evil as Hitler was.”

Nazi comparisons are often viewed as the end of a serious factual conversation and as the beginning of ideological mudslinging. “The danger also is that people will rally to defend the people who unfairly have been compared to Hitler and feel sorry for them, rather than to figure out what’s wrong with them,” Weber said.

Read more: 

What Germans really think about those Hitler-Trump comparisons