Washington • The art and protocols of effective diplomacy are coming under new scrutiny after a series of mostly off-the-cuff remarks by U.S. ambassadors that caused consternation abroad and at home.

At least four times in recent months — twice in the past week alone — envoys appointed by President Donald Trump have said things that have made professional diplomats question whether the current crop of political appointees is getting adequate training and understands the norms expected of ambassadors.

Over the weekend, the newly appointed ambassador to Germany Richard Grenell was accused of stepping over the line into partisan politics for saying in an interview with Breitbart News that he wants to “empower” conservatives throughout Europe.

It was Grenell’s second turn in the spotlight. After the United States withdrew from the Iran nuclear accord last month, he seemed to threaten German businesses investing there by advising that they should “wind down operations immediately.”

Last week, David Friedman, the ambassador in Jerusalem, told the Times of Israel that Republicans in the United States, “no question,” support Israel more than Democrats do. His remark provoked outrage among many career diplomats at the State Department who consider it a point of honor to represent the United States, not any political faction.

The incidents came after ambassadors elsewhere were chastised for public gaffes.

Peter Hoekstra, the ambassador to the Netherlands, was ridiculed by the Dutch media in January after he denied ever asserting there were “no-go zones” in the country’s Muslim enclaves. He dismissed it as “fake news,” and after his interviewer showed him a video of his 2015 remark, Hoekstra denied having used the term “fake news” minutes earlier. He eventually apologized and visited a Muslim neighborhood.

And last October, Scott Brown, the ambassador to New Zealand, was counseled on the State Department’s standards of conduct after he told women at a celebration in Samoa that they were “beautiful” and could earn “hundreds of dollars” in the hospitality industry.

Taken as a whole, the awkward asides suggest Secretary of State Mike Pompeo has his work cut out for him as he seeks to boost sagging morale and wrest control of U.S. diplomacy back from the White House.

“We’re sending out ambassadors who openly and almost intentionally are insulting not just host governments but host publics,” said Nancy McEldowney, a former director of the Foreign Service Institute charged with training diplomats and now at Georgetown University. “If this is how Mike Pompeo thinks he’s going to get the State Department’s swagger back, he’s going to find even more departures of career foreign officers who do not want to be party to this kind of bombastic and bullying appointees.”

In part, the incidents reflect the judgment calls ambassadors must make in promoting the administration’s policies without crossing the line into interference with a host country’s domestic politics.

But even relatively hard and fast rules can be ignored in some circumstances. Despite the general prohibition on delving into domestic politics in a host country, Robert Ford, a former ambassador to Syria, visited anti-government protesters in the city of Aleppo at the outset of the civil unrest to demonstrate U.S. support for human rights.

“If an ambassador is supporting human rights or press freedom, it can be seen as interference by the host country,” said Ronald Neumann, president of the American Academy of Diplomacy. “But that’s more normal business. Saying one party is more supportive of a country than the other is a very unusual statement to make in public.”

Grenell rejected the criticism directed at his statement on empowering European conservatives, saying he had just stated an observable fact.

“The idea that I’d endorse candidates/parties is ridiculous,” he tweeted. “I stand by my comments that we are experiencing an awakening from the silent majority - those who reject the elites & their bubble. Led by Trump.”

But Democrats in Congress were less forgiving.

“If Ambassador Grenell is unwilling to refrain from political statements, he should be recalled immediately,” said Sen. Jeanne Shaheen, D-N.H. “The United States does not accept foreign meddling in our elections, and we shouldn’t have an ambassador attempting to intrude in another country’s political affairs.”

State Department spokeswoman Heather Nauert defended Grenell’s and Friedman’s remarks as a matter of free speech.

“Our ambassadors advocate for American interests abroad,” she told reporters. “Each ambassador has his/her own personality and style. The challenge is to leverage that in the most effective way.”

But the incidents have reopened a long-running debate on the merit of the United States having so many political appointees in the diplomatic corps. Roughly a third of all U.S. ambassadors are political, chosen mostly because of their ties to the president or because they are big campaign donors. No other industrialized country in the world has so many political appointees.

Many political appointees become accomplished, admired envoys. But professional diplomats say the inexperience of some ambassadors causes embarrassing and damaging flaps that career diplomats rarely make.

Some State Department officials who have served in both Democratic and Republican administrations say colleagues and ambassadors who have come in with the Trump administration often are more resistent to advice from the career diplomats because they consider Foggy Bottom a bastion of liberal, “deep state” values. Others say only a handful of political appointees are dismissive of the briefings they undergo from experts in their region before they leave for posts.

“They are indicative of people who see themselves as the ambassador of Donald Trump as opposed to being the ambassador to the United States,” said Barbara Bodine, a former U.S. ambassador in the Middle East who is now with Georgetown University. “They reflect the attitude and viewpoint of the president, but not necessarily the long-term interests of the United States.”

All prospective ambassadors go through three weeks of training, known colloquially as charm school, before heading to the field. It includes ethnical considerations, security arrangements and managing an embassy staff. Political appointees also go through an extra three-day course to familiarize them with the State Department, an organization filled with confusing acronyms.

“If you have internalized your role as an ambassador, you’d know not to make comments like that,” Bodine said. “If you haven’t internalized where the lines are, and not just what’s appropriate but what’s effective, you’re not going to know when what you’re saying is going to cause offense.”

G. Philip Hughes, who was ambassador to several Caribbean island states during the administration of George H.W. Bush, said political and career diplomats in every administration make missteps, but they rarely get the coverage given to representatives of the Trump administration.

“I can think of examples of career foreign service officers who garnered shocking headlines locally for things they said publicly in speeches,” he said. “Ambassadors say controversial things all the time.”

“An ambassador wouldn’t be the first human being who answered a question on the spur of the moment that he later regretted or wished he’d said differently. It’s not the end of the world.”