David Holmes, political counselor at the U.S. embassy in Ukraine and one of the most knowledgeable witnesses scheduled for public testimony this week at the House impeachment hearings, says he was told that President Trump cares nothing about Ukraine, only about investigating Joe Biden.

When was he told this?

Just moments after Gordon Sondland, U.S. ambassador to the European Union, ended a phone conversation with Trump that Holmes overheard.

This comes from a 213-page transcript of Holmes’s previous closed-door deposition before the impeachment inquiry, released Tuesday and cited in an insightful analysis by Washington Post columnist James Hohmann.

In that testimony, Holmes recalled being at lunch with Sondland in Ukraine’s capital, Kyiv, on the day after Trump’s notorious July 25 phone call with Ukrainian President Volodymyr Zelensky, and shortly after Sondland himself met with Zelensky.

After ordering a bottle of wine … Sondland used his unsecured cellphone to update President Trump on his meeting that morning [with Zelensky], Hohmann writes. “Holmes said he could hear Trump say, ‘So he’s going to do the investigation?’ And he said Sondland responded, ‘Oh yeah, he’s going to do it.’”

“The investigation” is, of course, the one Trump asked Zelensky to pursue into Biden, his political rival, and Biden’s son Hunter — and into a debunked conspiracy theory that sought to blame meddling in the 2016 U.S. election on Ukraine instead of Russia.

But Hohmann writes that it’s not the 2-minute Trump-Sondland call that’s “most problematic”; it’s what came afterward, according to the Holmes transcript:

According to Holmes, the E.U. ambassador volunteered that the president cared more about the investigation of Joe Biden that Rudy Giuliani was pursuing than anything having to do directly with Ukraine.”

“Ambassador Sondland stated, the President only cares about ‘big stuff,’” Holmes testified, under oath. “I noted that there was ‘big stuff’ going on in Ukraine, like a war with Russia. And Ambassador Sondland replied that he meant ‘big stuff that benefits the president,’ like the ‘Biden investigation that Mr. Giuliani was pushing.’”

Holmes called that “an extremely distinctive experience” in his long Foreign Service career. And he thought the Russians were probably listening in.

“Waiters were coming and going as all this played out on the outdoor terrace at [the Kyiv restaurant],” Hohmann writes. “Holmes said he was surprised a presidential conversation so candid would take place on a cellphone since the Russians own or hold significant stakes in the [Ukrainian] mobile networks,” so officials should “assume” they’re being monitored.

“Holmes’s sworn testimony links Trump himself much more directly to the efforts to coerce Ukraine to investigate Biden at a time when the former vice president was leading in polls,” Hohmann writes. “It also further undermines another favorite GOP talking point: that Trump put assistance on ice because he was sincerely concerned about corruption and the rule of law in Kyiv.”

According to the transcript, Holmes testified that he thought “the Ukrainians gradually came to understand that they were being asked to do something in exchange” for an Oval Office meeting between Trump and Zelensky, and Trump’s release of nearly $400 million in military aid for Ukraine as voted by Congress.

There’s more, perhaps much more, to come: Sondland is scheduled to give public testimony to the impeachment inquiry on Wednesday. Holmes will do the same on Thursday.