That’s a curious thing to say about a man Mr. Trump appointed himself, and about whom he tweeted just last month, “I would love to send Ambassador Sondland, a really good man and great American, to testify.” In the next tweet, Mr. Trump highlighted an earlier assertion by Mr. Sondland, also in a tweet, that “the President has been crystal clear: no quid pro quo’s of any kind.” Mr. Trump added, “That says it ALL!”

Mr. Sondland had not said it all, as the nation learned Wednesday. In his initial congressional testimony in October, he claimed he had no conversations with Ukrainian officials about tying the investigations to the military aid. In fact, as multiple witnesses later testified, Mr. Sondland did speak with Ukrainians about the need for investigations, and had a very public phone call with the president in a restaurant about this subject. He then provided a written update to his testimony, and o n Wednesday, he testified that he had spoken to Mr. Trump by phone on July 26 and assured him that Mr. Zelensky was prepared to announce the investigations.

After everything else he remembered, it sounds like Mr. Trump’s allies are going to need some new defenses .

They started testing some out in real time, as lawmakers began to challenge Mr. Sondland’s recollection of certain events, even though the State Department has refused to release records that would help confirm or deny his recollection.

They hammered away at Mr. Sondland’s remark that Mr. Trump told him he “wanted nothing” from Ukraine, repeated “no quid pro quo” and never mentioned the Bidens. (Incidentally, on Wednesday morning Mr. Trump was carrying around these same talking points scrawled out in thick black marker, and later tweeted them out in all caps.)

Perhaps the president is unaware that simply saying he didn’t do something is not proof that he didn’t — especially when he has already provided the proof that he did do it. On the July 25 phone call that led to the whistle-blower’s complaint, Mr. Zelensky brought up the matter of the military aid, and Mr. Trump responded by saying he wanted Mr. Zelensky to “do us a favor, though” and announce both investigations, referring explicitly to Burisma and the Bidens.

You know what would help clarify some of these issues? Sworn testimony from the many key players in this scheme who have yet to appear before Congress, despite the fact that nearly all of them have been subpoenaed: Secretary of State Mike Pompeo; Mick Mulvaney, acting chief of staff; Mr. Perry, the energy secretary; the former national security adviser, John Bolton; Attorney General William Barr; John Eisenberg, the National Security Council lawyer; officials from the Office of Management and Budget; and, of course, Mr. Giuliani and his bagmen Lev Parnas and Igor Fruman. While they are at it, Congress could invite Mr. Trump and Vice President Mike Pence to testify.