The drip, drip of revelations from the House Democratic impeachment probe of President TrumpDonald John TrumpFederal prosecutors investigating Giuliani: report House Foreign Affairs Committee Chairman and top Republican to introduce sanctions bill against Turkey Trump lashes out at 2020 Dems, impeachment inquiry MORE is continuing to create bad headlines for the White House, marring its efforts to push back on the issue.

The latest negative news from the White House’s perspective came Friday, when the former U.S. ambassador to Ukraine excoriated the administration in closed-door testimony on Capitol Hill. 

According to reports, Marie Yovanovitch said she had been told that Trump had pressed for her ouster, despite officials at the State Department contending she had done nothing wrong. Yovanovitch said she was “incredulous” at her removal, according to a copy of her opening statement obtained by The New York Times.

Yovanovitch’s testimony itself was somewhat of a surprise. Many expected she would not appear after the White House said Tuesday it would not cooperate with the impeachment inquiry.

But Democrats subpoenaed for Yovanovitch’s testimony, and the diplomat clearly wanted to tell her story.

Separately, the U.S. ambassador to the European Union, Gordon Sondland, said in a statement that he would testify next week. Sondland’s testimony is likely to be friendlier to the White House, but it still has the potential to lead to some damage.

Democrats also want to talk to other figures in the Ukraine controversy, including diplomat William Taylor, who believed Trump wanted to withhold aid to Ukraine unless it launched an investigation of former Vice President Joe BidenJoe BidenFederal prosecutors investigating Giuliani: report Trump lashes out at 2020 Dems, impeachment inquiry In marathon testimony, Dems see an ambassador scorned, while GOP defends Trump MORE. Taylor is the U.S. chargé d'affaires in Ukraine.

Energy Secretary Rick PerryJames (Rick) Richard PerryOvernight Energy: Advisory panel pushes park service to privatize campgrounds | Dems urge Perry to keep lightbulb efficiency rules | Marshall Islands declares national climate crisis Cracks emerge in White House strategy as witness testifies Democrats urge Rick Perry not to roll back lightbulb efficiency rules MORE and Fiona Hill, a former staffer on the National Security Council who left the White House in August, are also on the Democratic wish-list.

All of these developments came hot on the heels of the arrest of two associates of Rudy GiulianiRudy GiulianiFederal prosecutors investigating Giuliani: report In marathon testimony, Dems see an ambassador scorned, while GOP defends Trump Arrested Giuliani associate attended Trump's invite-only 2016 election night party: report MORE, the president’s personal lawyer. The two men, both with ties to Eastern Europe, have been accused of violating campaign finance laws. They were arrested at Dulles International Airport near Washington, as they attempted to leave the country.

The steady stream of new developments has left Republicans wondering what more is still to come — a dynamic that has hampered the White House’s efforts to marshal party support behind a coherent message.

“Obviously there is a ton of bad [news] out there,” said GOP strategist Liz Mair. “It is getting to be overwhelming. It is getting to the point where a lot of people are getting fed up.”

The White House had come under criticism, even in Republican circles, for rotating through different justifications for the president’s actions regarding Ukraine since details first emerged last month about a July 25 phone call between him and Ukrainian President Volodymyr Zelensky.

On that call, Trump pressed Zelensky to open an investigation into Biden and his son Hunter.

Speaker Nancy PelosiNancy PelosiTrump lashes out at 2020 Dems, impeachment inquiry In marathon testimony, Dems see an ambassador scorned, while GOP defends Trump Trump accuses Pelosi of 'hating' US over impeachment inquiry MORE (D-Calif.) came out in favor of impeachment proceedings on Sep. 24 but it is only in the past week that the administration appears to have settled on a counter-message: that impeachment is not merely partisan but a de facto coup attempt against Trump.

The president has made this point in his tweets and it was reiterated in a letter to Pelosi and other top Democrats from White House counsel Pat Cipollone earlier this week.

Trump aide Stephen MillerStephen MillerTrump says acting Homeland Security chief McAleenan will step down Overnight Health Care — Presented by Coalition Against Surprise Medical Billing — Judge blocks Trump 'public charge' rule | Appeals court skeptical of Trump arguments for Medicaid work requirements | CDC offers guidance for treating vaping-related cases Cracks emerge in White House strategy as witness testifies MORE, during characteristically combative exchanges with reporters at the White House on Friday, complained about “the corruption of the permanent bureaucracy, also known as the Deep State” and “Washington Democrats that are engaged in this scam and witch hunt.”

Earlier in the day, Trump had decried the whistleblower complaint that set the current train of events in motion as “a giant scam.” In fact, the account of the phone call as presented by the whistleblower was confirmed by records released by the White House.

The spiraling crisis has had a significant effect on the president’s standing in opinion polls. The president took umbrage at a Fox News poll released late Wednesday that showed 51 percent of voters favoring his impeachment and removal from office.

Trump argued on Twitter the next day that, whoever Fox’s pollster was, “they suck”. 

But there have been a number of polls from other organizations that have also shown public opinion shifting in favor of impeachment. 

Support is higher for an impeachment inquiry now than it was in the wake of the publication of former special counsel Robert MuellerRobert (Bob) Swan MuellerFox News legal analyst says Trump call with Ukraine leader could be 'more serious' than what Mueller 'dragged up' Lewandowski says Mueller report was 'very clear' in proving 'there was no obstruction,' despite having 'never' read it Fox's Cavuto roasts Trump over criticism of network MORE’s report into allegations of collusion with Russia.

Trump allies are hoping they can apply lessons from the Mueller experience to their current predicament, however. Mueller came under sustained attack from Team Trump throughout his tenure, and there is some evidence that this eroded his standing with the public.

It is plausible that a similarly intense assault on Democrats over impeachment could have a comparable effect. If that occurs, the current opinion polls could represent a high-water mark in terms of support for impeachment. 

But such an outcome is far from certain, especially if the drip, drip of bad headlines continues.

Such news “becomes an automatic, daily pushback of anything the White House is trying to do,” said Doug Heye, a former communications director of the Republican National Committee.

Referring to Trump’s rally in Minneapolis on Thursday evening, Heye said, “Trump said last night, ‘Isn’t it better when I go off-script?’ Well, the reality is that all of these things guarantee that the administration stays off-script.”

Asked if the administration could get back on an even keel, Heye demurred.

“I don’t think they ever were on an even keel,” he said, “Part of that was by design. Disruption was always going to be a part of this presidency just as it was during the campaign — and ultimately the campaign was successful.

“The challenge for them now is where this goes.”

The Memo is a reported column by Niall Stanage, primarily focused on Donald Trump’s presidency.