When confronted with the whiff of scandal, American diplomats are often advised to resign if they believe they can no longer be effective in the job.

But for Gordon Sondland, the embattled U.S. ambassador to the European Union, quitting is not in the cards.

“He has no intention of resigning,” Sondland’s attorney, Jim McDermott, said in a statement to The Washington Post.

The Portland hotel magnate and GOP megadonor upended the House impeachment inquiry last week by acknowledging he communicated the terms of a quid pro quo with Ukraine during a meeting in September after testifying earlier that he had no knowledge of such an arrangement.

The reversal of his testimony prompted key Republican allies in the White House and Congress to abandon Sondland after initially viewing him as an indispensable witness.

Further revisions of his testimony may come next Wednesday, when he is expected to return to Capitol Hill to address a previously unknown July 26 phone call he had with Trump that Ambassador William B. Taylor Jr. revealed this week.

Sondland’s attorney said his client “has the full confidence of Secretary [Mike] Pompeo,” but the State Department declined to comment on that claim, adding to the diplomat’s isolation as he comes under fire from all sides.

The tension has left a wounded diplomat in charge of managing America’s relationship with the world largest trading bloc amid continuing challenges to his credibility.

Trump publicly distanced himself from his envoy last week, telling reporters “I hardly know the gentleman” after praising him as a “great American” just days earlier.

Top Republicans in Congress also have turned on Sondland and began circulating unsubstantiated rumors suggesting he had been co-opted by the Democrats.

“Why did [Sondland] change his testimony?” asked Sen. Lindsey O. Graham of South Carolina. “Was there a connection between [Sondland] and Democratic operatives on the committee?”

Sondland’s revised statement was “full of crap,” Graham said.

Democrats, some of whom already accused Sondland of committing perjury, applauded his acknowledgment last week that the Trump administration had linked about $400 million in U.S. military aid to investigations into former vice president Joe Biden and his son, who worked at a Ukrainian energy company. Sondland said he now remembered those conversations after the testimony of others “refreshed my recollection,” a remark widely lampooned on late-night television.

But Democrats privately concede that Sondland isn’t an ideal witness for them either because he now lacks credibility.

The newest source of interest for Democrats is a July phone call Sondland had with Trump in which the president asked about the status of the “investigations” he sought from Ukraine, according to Taylor’s testimony. After Sondland hung up the phone, he told an aide to Taylor that “Trump cares more about the investigations of Biden” than about Ukraine itself, according to Taylor.

Taylor’s account offers another indication that Sondland was deeply familiar with the campaign to pressure Ukraine into investigating the Bidens dating back to July, raising more questions about Sondland’s original testimony. Sondland had told investigators he was “quite shocked” when Taylor texted him in September about his concern that the Trump administration was linking the investigation into the Bidens to U.S. assistance for Ukraine.

Despite the growing scrutiny of Sondland’s honesty and credibility, his attorney said Sondland has “not felt any pressure to resign.”

“Just last week, Secretary Pompeo expressed his full confidence in Ambassador Sondland directly to him,” McDermott said. Sondland declined to comment for this article.

Many question how he can continue to represent the United States after being undercut by the president and his allies.

“One of the main currencies Sondland has traded on as ambassador has been his close personal relationship with President Trump, so to have that rug publicly pulled out from under him is a blow to his credibility and effectiveness,” said Molly Montgomery, a former career diplomat who advised Vice President Pence.

Sondland isn’t the only official in an awkward position after providing testimony. Lt. Col. Alexander Vindman, a White House official, told House investigators that Trump’s July 25 phone call with Ukrainian President Volodymyr Zelensky was “wrong” but remains at the National Security Council overseeing Ukraine policy. When asked whether he would be removed from the job, national security adviser Robert O’Brien told CBS on Sunday that Vindman would return to the Pentagon when his rotation finishes, which his lawyers say is scheduled for July 2020.

Other State Department officials who raised concerns behind closed doors also remain on the job, though they have not drawn the same level of scrutiny as Sondland, who spearheaded Trump’s Ukraine policy alongside the president’s personal attorney Rudolph W. Giuliani.

One former official said the Trump administration’s denial of wrongdoing in the Ukraine controversy prevents it from putting pressure on someone like Sondland to step down.

“In most administrations, the White House would instruct an ambassador in the midst of a scandal to step aside if they can no longer be effective,” said a former Trump official, who like others spoke on the condition of anonymity to discuss Sondland’s situation. “But this administration is not conceding that there’s a controversy. Their attitude is: Why would we want him to go? It’s admitting that he’s done something wrong.”

Sondland’s refusal to step down also comes after his current and former colleagues heavily criticized his actions under sworn deposition.

Vindman said he “tended to go off script” and was “not a professional diplomat.” Former White House official Fiona Hill called him a walking “counterintelligence risk” and “target for foreign powers.” She said Sondland “frequently” gave foreign officials her cellphone number to “call up and demand meetings.”

“We had all kinds of officials from Europe . . . literally appearing at the gates of the White House,” Hill said. “He was . . . giving out his phone number and texting [regional officials]. . . . All of those communications could have been exfiltrated by the Russians very easily.”

Hill testified that Sondland had good intentions but that in terms of policy, “he’d just gone off the road. No guardrails, no GPS.”

Sondland’s isolation continues even inside the U.S. mission in Brussels, where some career diplomats said they had been appalled by his leadership.

Not long after arriving there, Sondland started talking to subordinates about a need for more skilled and wealthy European immigrants in the United States in an attempt to ease tensions with the European Union, according to a person familiar with his views.

Many U.S. diplomats in the mission were unsettled by the idea, viewing it as racially motivated. One diplomat said that “the way this was going to come off was that the United States is fishing for white people, while reducing opportunities for needier people to immigrate.”

The person familiar with Sondland’s views said Trump had tasked him in July 2018 with developing a proposal to “fast track” immigration from the E.U. in consultation with the president’s main immigration adviser, Stephen Miller, and son-in-law Jared Kushner.

“The proposal languished and was eventually dropped,” the person said. “Ambassador Sondland did not understand that the proposal was racially or ethnically motivated.” It would have encompassed all E.U. countries, the person said.

Other people said Sondland abused his position of power, such as by pursuing a $1 million taxpayer-funded home renovation and bringing his dog to work and asking subordinates to walk it for him.

Sondland’s attorneys said the renovations were necessary and denied the account about his pet, saying “multiple people at the mission enjoy having Ambassador Sondland’s dog around. One person in particular has repeatedly asked Ambassador Sondland to walk his dog. No one has ever been ordered to walk Ambassador Sondland’s dog.”

Sondland was initially received by European officials in Brussels with relatively open arms at the beginning of his posting in July 2018. He delivered a quick, if symbolic win — reversing a Trump administration decision to downgrade the status of the E.U. ambassador in Washington, which affected how the diplomat is seated at dinners, when the envoy is invited to receptions and in what order the diplomat is called to pay respects at state funerals. (Local observers noted that without Sondland’s intercession, he would have been downgraded in the same way in Brussels, so it was in his own interest to get the decision withdrawn.)

But the initial warmth quickly reversed. Officials soon became frustrated with Sondland, who appeared to know little about Europe or the European Union and tried to push leaders of E.U. institutions to make concessions that were not in their power to grant, officials said.

On issues ranging from the Iran nuclear deal to trade talks to recognizing Jerusalem as the capital of Israel, Sondland demanded that European officials support Washington’s positions, one E.U. diplomat said. The problem was that their views reflected the carefully negotiated consensus of all 28 E.U. countries, meaning that shifts in policy had to come from national capitals — not officials inside the E.U.’s sprawling bureaucracies.

“In tone, manner and content he exuded disrespect and abominable lack of knowledge of Europe and the European Union,” said Nathalie Tocci, the director of the Italian International Affairs Institute and an adviser to E.U. foreign policy chief Federica Mogherini. “On top, the attitude was clearly that of someone who viewed the E.U. not simply as a competitor or even rival, but as an outright adversary.”

Sondland’s decision to hang on differs from the path chosen by Kurt Volker, the former U.S. envoy for Ukraine who worked closely with Sondland before stepping down in September. The contrast in the two approaches may stem from Volker’s background as a career diplomat, said the former Trump official.

“Kurt comes from the foreign policy establishment, where the norm is that if you’re involved in a controversy and you’re no longer effective, the correct thing to do is to step down,” the former official said. “In contrast, Sondland has seen many Trump officials survive scandals by hunkering down and weathering the storm, so they’re likely guided by two different norms.”

Birnbaum reported from Brussels. Shane Harris in Washington contributed to this report.