The Nixon-era political trickster was found guilty of lying to Congress and witness tampering, apparently motivated by a desire to protect Trump from embarrassment over the Russia scandal.
"Truth matters. Truth still matters, OK?" prosecutor Michael Marando had told the jury on Wednesday. "In our institutions of self-governance, committee hearings, courts of law ... truth still matters."
And on Friday evening, things took another turn for the worse for Trump.
Diplomatic aide David Holmes testified that he had heard Trump on a telephone call ask US Ambassador to the European Union Gordon Sondland whether the Ukrainians were going to open investigations he had asked for into former Vice President Joe Biden and a conspiracy theory surrounding the 2016 election.
Sondland told Trump on the call in July that Ukranian President Vlodymyr Zelensky was ready to do "anything you ask him to," according to a transcript of an opening statement delivered by Holmes to a closed-door session of the impeachment investigation.
The revelation significantly raised the stakes for Sondland's testimony in a televised hearing next week and suggests that Trump was intimately involved in his lawyer Rudy Giuliani's scheme to pressure the Ukrainians.
Whether Americans ultimately come to believe that the President's alleged misconduct merits the terrible sanction of removal or come to believe the Democratic impeachment attempt is narrowly political and unjustified, this was a clarifying day.
At a time of swirling misinformation, propagandistic pro-Trump news coverage and conspiracy theories, it showed that while facts may be under assault, they can ultimately still emerge in a way that will allow history to render a judgment even if the fractured political climate makes that it impossible in the moment.
Friday piled more testimony on the mountain of evidence suggesting that the US is in the grip of not just the most unorthodox, but the most corrupt presidency of the modern era.
The Stone and Yovanovitch dramas did not take place in isolation. They fit into a pattern of questionable behavior clouding Trump's entire political career. The sheer weight of such evidence confounds his supporters' claims that the real problem is that Democrats and the media are caught up in some kind of "Never Trump" mania that amounts to a coup.
This, after all, is a President who demanded misplaced personal loyalty from FBI chief James Comey, then fired him and said he did it because of the Russia investigation. Trump also repeatedly berated his first Attorney General Jeff Sessions for honoring an obligation to recuse himself from the Russia probe.
While special counsel Robert Mueller did not establish cooperation between Trump's campaign and Russia, he said the President's team expected to benefit from his election meddling.
And he pointedly did not exonerate Trump of obstruction.
For sure, there are legal questions about immunity and the extent to which an individual in that job should expect financial privacy at play here.
But Trump's move still raised the question about what he has to hide from the people for whom he holds a public trust.
The human toll of the Ukraine scandal
Yovanovitch's only offense may have been that she got in the way of a plan by Giuliani, working at Trump's direction, to get the Ukrainian government to investigate one of the President's domestic political opponents -- Biden.
It was notable that while Republicans on the House Intelligence Committee protested the process and highlighted that Yovanovitch was gone before Trump's alleged scheme to get dirt on Biden came to fruition, they did little to counter her story of a back door diplomatic scheme led by Giuliani.
Democrats scheduled the former ambassador in their second televised impeachment hearing to suggest the human cost of the President's Ukraine scheme.
She also helped them flesh out an argument that Giuliani, acting at the direction of the President, and with associates in Ukraine like now indicted Lev Parnas and Igor Fruman, had trampled over America's foreign policy interests in pursuit of their own personal and political enrichment.
Yovanovitch also found herself the target of a fierce campaign by conservative pundits that including the President's son, Donald Trump Jr.
Far from working to drain corruption as Yovanovitch was in Ukraine, she testified that Giuliani's team was working with corrupt figures in Kiev and importing their methods to the US.
Like her colleagues, George Kent and Bill Taylor who testified Wednesday, she seemed like an envoy to a country she no longer understood -- her own -- where governance is beginning to share characteristics of corruption-laced nations where they served.
"How could our system fail like this?" Yovanovitch asked.
"How is it that foreign corrupt interests could manipulate our government? Which country's interests are served when the very corrupt behavior we have been criticizing is allowed to prevail?" Yovanovitch said.
Like other witnesses from the foreign service bureaucracy, Yovanovitch also warned that current turmoil will damage America's reputation.
"Such conduct undermines the US, exposes our friends and widens the playing failed for autocrats like President Putin," she said. "Our leadership depends on the power of our example."
Trump's tweet in which he accused Yovanovitch of making each country that she served in -- for instance Somalia -- worse, only lent credibility to her account of feeling intimidated by the commander-in-chief's smears and threats.
Several Republicans decried Trump's attack as counterproductive.
"It was idiotic to tweet today about her," one Trump campaign source told CNN's Jim Acosta. "She seems legitimately worried."
The President's intervention could be a sign that he understood the damage the ambassador's testimony was doing. But he insisted later that he had every right to go after her.
"You know what? I have the right to speak. I have freedom of speech just as other people do, but they've taken away the Republicans rights," the President said.
It's unclear whether the tweets reach a standard of witness tampering that might stand up in court. Democrats suggested they could become part of eventual articles of the political process of impeachment in any case.
But the attack couldn't have been a clearer sign of the intimidation that characterizes Trump orbit.
And the assault by the most powerful man in the world will surely be on the mind of witnesses called to testify in next week's frenetic week of impeachment theater.
Trump rails at 'double standard'
Stone's conviction stems directly from the Mueller investigation. He was accused of lying about his efforts to contact Wikileaks to get information that could have helped Trump during his 2016 election campaign against Hillary Clinton.
Prosecutors argued that his crimes were partly motivated by a desire to save the President from political embarrassment.
Stone became the sixth Trump associate to be convicted -- a list that includes former campaign chairman Paul Manafort, former Trump lawyer Michael Cohen, the campaign's ex-deputy chairman Rick Gates, short-lived national security adviser Michael Flynn and former campaign foreign policy advisor George Papadopoulos.
So far, the President has largely avoided such legal consequences. But each of these men now has cause to regret their decision to jump aboard the Trump train. If a man is judged by the company he keeps, their convictions reflect poorly on the President.
Trump reacted furiously to Stone's conviction, claiming his fate at the hand of a jury of his peers was another example of an establishment plot against him.
"So they now convict Roger Stone of lying and want to jail him for many years to come," Trump tweeted, before raging at his usual punching bags including Clinton, Comey and Obama administration intelligence community officials.
"A double standard like never seen before in the history of our Country?" the President wrote.
Speculation is already running high that the President could use his power to pardon Stone -- a move -- at the time of an impeachment drama that would be politically radioactive.
The President has exceedingly broad power to pardon offenders, but saving Stone would suggest that people around him are above the law. And it would further color in a portrait of rampant corruption already threatening to dominate his legacy.