If someone held a competition to determine the most head-shaking of Donald Trump’s personnel decisions, there’d be several top contenders, but Richard Grenell would have to be in the mix.

To know anything about Grenell, a former U.S. spokesman at the United Nations, is to know he’s spent the last several years annoying quite a few people as an internet troll. I generally try to avoid blocking people on Twitter, but even I found Grenell’s juvenile antics so grating that I took advantage of the platform’s “block” feature.

After one exasperating exchange in 2012, the Washington Post’s Dave Weigel asked him, “Shouldn’t you eventually get a job and quit trolling people?”

As it turns out, Grenell did get a job: Donald Trump nominated him to serve as U.S. ambassador to Germany, and in late April, Senate Republicans ignored Democratic concerns and confirmed him.

Two weeks later, Grenell was sworn into office, and within hours, he was already offending his German hosts, threatening German companies that do business with Iran. As NBC News reported this morning, the new ambassador went quite a bit further in an interview with a far-right American website.

The U.S. ambassador to Germany has said he aims to “empower” European conservatives who are “experiencing an awakening from the silent majority.” “I absolutely want to empower other conservatives throughout Europe, other leaders,” Ambassador Richard Grenell told the conservative news website Breitbart in an interview posted Sunday. “I think there is a groundswell of conservative policies that are taking hold because of the failed policies of the left. There’s no question about that, and it’s an exciting time for me.” He added, “That’s a very powerful moment when you can grasp the ability to see past the groupthink of a very small elitist crowd telling you you have no chance to win or you’ll never win, or they mock you early on.”

There are three basic elements to keep in mind with a story like this. First, many German officials were already unimpressed with the Trump administration – the American president has alienated German Chancellor Angela Merkel on multiple fronts – and the Republican president dispatching Grenell to Berlin obviously will not help improve the important relationship.

Second, the ambassador is apparently confused about the nature of his responsibilities, forgetting that he’s in Germany representing all of us, not just those who share his ideology. From the NBC News report:

“It’s totally out of line for a U.S. ambassador, particular to a friendly country, to make comments that associate himself with one lane of the political spectrum in the host nation,” said Stewart Patrick, a senior fellow at the Council on Foreign Relations, who focuses on international cooperation. “This is a NATO ally and one of our closest partners in Europe and the last thing he should be doing is inserting himself in its political future,” he added. “If the shoe was on the other foot, Americans would be appropriately outraged.”

Sen. Chris Murphy (D-Conn.), a member of the Senate Foreign Relations Committee, added yesterday, “When I raised concerns to Grenell about politicizing this post, he personally assured me that once he became ambassador he would stay out of politics.” Evidently, the Republican is now going back on that promise.

And finally, it’s worth appreciating the fact that Grenell isn’t alone in his abandonment of diplomatic norms: Trump’s ambassador to Israel, David Friedman, spoke to an Israeli newspaper and condemned Democrats in the United States.

I don’t know when American norms will be restored, but I know it won’t be anytime soon.