Martin Schulz, the president of European parliament, is echoing widespread concerns outside the United States about the destabilizing consequences of a Donald Trump presidency.

For months, the American business mogul's run for the White House has been the source of international bemusement and disquiet. Trump's isolationist foreign policy and far-fetched proposals — from getting Mexico to pay for a border wall to barring Muslim immigrants to somehow seizing all of Iraq's oil — has drawn an unprecedented string of criticism from myriad foreign dignitaries.

And as the election draws nearer, the chorus of condemnation may grow louder.

"Trump is not just a problem for the E.U., but for the whole world," Schulz said in an interview with German magazine Der Spiegel.

Schulz linked the Trump phenomenon to far-right populism in Europe, which is threatening the unity of the European Union, a political project loathed by far-right, nationalist parties throughout the continent.

"When a man ends up in the White House who boasts about not having a clue and who says that specialist knowledge is elite nonsense, then a critical point has been reached," said Schultz, a center-left German politician who has been president of the E.U.'s legislature since 2012. "Then you will have an obviously irresponsible man sitting in a position that requires the utmost degree of responsibility. My worry is that he may inspire copycats, also in Europe. That's why I hope Hillary Clinton wins."

Schulz's endorsement of Clinton surprised his interviewer, who pointed out that even German Chancellor Angela Merkel has shied away from such strong, partisan language.

"I say what I think about Trump," he replied, adding that if Trump wins the election and visits the European parliament, "we will receive him just as we have every other U.S. president."

In the interview with Der Spiegel, Schulz also articulated his profound fears for Europe's political future. Britain's vote to initiate a "Brexit" and leave the bloc — an act cheered on by Trump — was a huge blow to Brussels. Right-wing populist parties in Western Europe have called for their own national "exits," while a host of conservative governments in Eastern and Central Europe have infuriated Brussels policymakers with their categorical refusal to cooperate in continental efforts to resettle refugees.

"We're at a historical juncture: A growing number of people are declaring what has been achieved over the past decades in Europe to be wrong. They want to return to the nation-state," Schulz told Der Spiegel.

He drew a dark comparison to the historical moment that preceded the rise of fascism: "Sometimes there is even a blood and soil rhetoric that for me is starkly reminiscent of the interwar years of the past century, whose demons we are still all too familiar with. We brought these demons under control through European structures, but if we destroy those structures, the demons will return. We cannot allow this to happen."

More on WorldViews