Speaking to the German magazine Der Spiegel, Juncker said that "the demons haven't been banished, they are merely sleeping," comparing fascism in the 1930s with rising populism and nationalism across Europe today.
In relation to traditional notions of peace and unity, Juncker said that "anyone who believes [that] the eternal issue of war and peace in Europe has been permanently laid to rest could be making a monumental error".
“I am chilled by the realisation of how similar circumstances in Europe in 2013 are to those of 100 years ago,” he said, referring to the growth of Eurosceptic and nationalist parties with electoral success in European countries including the United Kingdom, Austria and the Czech Republic.
In Austria, a public opinion poll showed that 42% of the population thinks that "Hitler wasn't all bad", while 57% believed "there was nothing positive about the Hitler era". Finland and Italy have also both witnessed a steep increase in support for Eurosceptic parties lately.
In the interview, the Prime Minister of Luxembourg emphasised his generations’ focus on peace through monetary union, while warning of a chilling tendency among today’s Europeans of "returning to a regional and national mindset".
With the Eurocrisis, he focused on rising animosity between countries such as Greece and Germany, pointing towards dangerous ‘un-European’ trends, which many thought had been "finally relegated to the past".
“The way some German politicians have lashed out at Greece when the country fell into the crisis has left deep wounds there. I was just as shocked by the banners of protesters in Athens that showed the German chancellor in a Nazi uniform,” he said.
But Juncker also said that Greece could no longer expect solidarity from other eurozone members if appropriate reforms were not fulfilled.
The very possibility of bankruptcy should encourage Athens to "get muscles" when it comes to implementing reforms, he said. "If we were to establish that everything has gone wrong in Greece, there would be no new programme, and that would mean that in March they have to declare bankruptcy".
Greece's government on Saturday continued talks with international lenders to secure the next payment in its €130 billion bailout while seeking backing for unpopular reforms involved in the rescue.
Democracy and its limits
Luxembourg's Prime Minister stressed that European countries can no longer avoid tackling the rising problem of debt, no matter what election results might bring.
“The consequence of the Italian election result cannot be that we suddenly return to the policies that caused this mess. It is not possible to combat the financial and economic crisis by saddling an already heavily indebted state with new debts. There is no getting around a solid budgetary policy," Juncker said.
“I'm going to make a bold statement: One shouldn't pursue the wrong policies just because one is afraid of not being reelected. Those who intend to govern have to take responsibility for their countries and for Europe as a whole. This means, if need be, that they have to pursue the right policies, even if many voters think they are the wrong ones” Junker said.
“Of course politicians should respect the will of the people as much as possible, provided they adhere to the European treaties. If the Italians intend to roll back the real estate tax, then they will have to come up with some other way of meeting their commitments. In Europe, even more so than in national politics, we have to follow the principle laid down by Martin Luther: Use language that the people will understand, but don't just tell them what they want to hear.”
'Off the world’s radar’
Juncker also highlighted the significance of the EU in world affairs and Europe’s role abroad.
“A united Europe is our Continent's only chance to avoid falling off the world's radar. The heads of government of Germany, France and the United Kingdom also know that their voice is only heard internationally because they speak through the megaphone of the European Union,” he said.
“Future-related issues are no less pressing. By the middle of this century, Europe will comprise only a good 7% of the world's population. Already today, over 80% of economic growth comes from other regions of the globe”.