The targeting of Ms. Yovanovitch is under investigation — by Ukrainian authorities, at least. Neither the Justice Department nor the State Department has announced an official inquiry into the matter, although on Thursday the F.B.I. visited Mr. Hyde’s home and business.

Russians hacked the Ukrainian gas company central to the impeachment inquiry.

President Trump wanted Ukraine’s new president, Volodymyr Zelensky, to announce an investigation of Burisma, the gas company on whose board Hunter Biden sat, as a way of enhancing his re-election prospects. The Times this week reported that Russian military hackers had bored into the email accounts of a number of Burisma subsidiaries, perhaps searching for material embarrassing to the Bidens. The tactics used were similar to those of Russian hackers in the 2016 campaign, when they breached the servers of the Democratic National Committee and the Clinton campaign. Ukraine has asked the F.B.I. to investigate.

President Trump personally directed the scheme to gather Ukrainian dirt on Joe Biden.

Mr. Trump and his allies have insisted that he was pursuing investigations of Joe and Hunter Biden, as well as of Ukraine’s alleged interference in the 2016 election, not for any personal political reason but as part of the American government’s longstanding efforts to address corruption in that country.

This claim was never believable, but now we know the president’s own top aides debunked it. In a May letter, Rudy Giuliani, Mr. Trump’s personal attorney, requested a meeting with Mr. Zelensky, then Ukraine’s president-elect, “in my capacity as personal counsel to President Trump and with his knowledge and consent.” Mr. Giuliani has been leading the charge to drum up charges of corruption by the Bidens, even visiting Ukraine to do more digging while the inquiry was underway. If Mr. Trump truly cared about rooting out systemic corruption, why was he sending his personal lawyer to do the job?

The answer is that the requested investigations were “a domestic political errand,” as Fiona Hill, a Russia expert who worked for the Trump administration, testified before Congress during the impeachment hearings.

Nor were people like Mr. Parnas rogue actors. On Wednesday, Mr. Parnas told The Times, “I am betting my whole life that Trump knew exactly everything that was going on that Rudy Giuliani was doing in Ukraine.”

President Trump personally ordered the hold on the Ukraine aid, even though top White House officials disagreed over the wisdom and legality of that move.