Germany is outraged. Only hours after right-wing media outlet Breitbart released an interview with the new US ambassador to Germany, Richard Grenell, some are calling for his expulsion. In it, the Donald Trump appointee expressed his desire to empower conservative, anti-establishment movements in Europe. Many of his talking points would have roused applause from the far-right Alternative for Germany (AfD) party: the passages referencing a silent majority, the welfare of the average worker, as well as those criticizing Germany's current refugee policies and describing an out of touch political elite. It isn't the first time that Grenell has so explicitly waded into internal German affairs. Shortly following his appointment, he demanded that German businesses halt trade with Tehran in reaction to the trans-Atlantic dispute over the Iran nuclear deal.

Read more: Who is Richard Grenell, the US ambassador to Berlin?

Unheard of

It is unheard of that an ambassador would so explicitly interfere with the internal affairs of his host country. Traditionally, such posts have been used to clarify their country's interests, build diplomatic bridges and resolve conflicts. But those who are shocked by Grenell's tradition-defying tactics have not yet understood that, with Trump in the White House, everything — including diplomacy — has changed. Trump is a businessman, and has found his greatest success in show business. His understanding of politics has little to do with "the art of the possible," as the father of German unification, Otto von Bismarck, defined it.

As with all populists, Trump and his team are most concerned with what churns up the biggest waves. Grenell knows precisely what he is doing when he talks about chain migration and praises Austria's hardline conservative chancellor, Sebastian Kurz. He wants to encourage those in Europe who, like Trump, challenge the status quo. In this interview, he is speaking to right-wing nationalist governments on the continent, like those in Poland and Hungary, who are critical of Europe in its current form.

Attempting to weaken European unity

Grenell, like his boss, is exploiting fears to advance his agenda. He is putting pressure on the weaknesses of the European system to advance a new order — one that weakens European unity primarily to benefit the United States.

Neither screams nor resignation will help to counter this strategy. Trump will always win in a shouting contest. Germany and its European partners have no choice but to accept that they can't rely on him. On the contrary, they must accept that the US president is threatening a trade war, and is using one of his most influential diplomats in Europe to hasten continental divisions.

There can only be one answer to this new trans-Atlantic relationship: an agreement with a clear vision for the future of the EU. One in which not only the big, but also the smaller countries find their place. As difficult as it is to accept: the EU's former ally has become a danger to its internal unity. After this interview, there is no doubt about that.