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In a stunning reversal that further confirms the notion of a quid pro quo, US Ambassador to the European Union Gordon Sondland says that after he first testified, he began to remember fresh details about a link between US security aid and Ukrainian investigations of President Donald Trump's political rival Joe Biden.

Sondland filed and the House Intelligence Committee released a three-page sworn addendum to congressional testimony Tuesday in which he said that reading testimony from other witnesses reminded him of some key details. Here they are:

Why is this so important?

Sondland is the GOP donor and political appointee who was in direct contact at times with Trump about Ukraine. And now he remembers what amounts to a direct quid pro quo, although he still can't remember everything.

Tale of the transcripts

Sondland's new memory is far from the only big news from the impeachment inquiry today. The House Intelligence Committee released transcripts of testimony by Sondland and former special envoy for Ukraine Kurt Volker.

CNN's had a team reading through both sets of transcript s line-by-line and writing on them in real time.

Here are some of the new things we've learned:

SONDLAND

VOLKER

This White House response

Here, printed in full, is the response from White House press secretary Stephanie Grisham:

"Both transcripts released today show there is even less evidence for this illegitimate impeachment sham than previously thought. Ambassador Sondland squarely states that he 'did not know, (and still does not know) when, why or by whom the aid was suspended.' He also said he 'presumed' there was a link to the aid—but cannot identify any solid source for that assumption. By contrast, Volker's testimony confirms there could not have been a quid pro quo because the Ukrainians did not know about the military aid hold at the time. No amount of salacious media-biased headlines, which are clearly designed to influence the narrative, change the fact that the President has done nothing wrong."

What whistleblower?

What's not really an issue in either transcript or the White House response is the whistleblower, whose importance to the impeachment case against Trump is waning even as the President's focus on the whistleblower grows.

And that's a real problem since under US law, the person in charge of protecting the whistleblower is ... Trump.

I spent time looking into what protections US law actually provides whistleblowers. They're not what you think.

The Podcast

CNN political director David Chalian discusses the electoral implications with CNN chief political analyst Gloria Borger and CNN White House reporter Maegan Vazquez talked about Sen. Rand Paul's call, standing next to Trump in Kentucky, for the media to report on the identity of the whistleblower. It's Election Day in Kentucky and the governor is on the ballot. Listen here.

What's coming

What transcripts will be released tomorrow? We don't yet know.

Who will testify? We don't entirely know.

Investigators have requested testimony from Energy Secretary Rick Perry, acting Office of Management and Budget Director Russ Vought and David Hale, a State Department official. State Department counselor Ulrich Brechbuhl, whose testimony was also sought, is instead traveling with Secretary of State Mike Pompeo to Germany on Wednesday, according to a pool report.

What else?

White House acting chief of staff Mick Mulvaney to testify on Friday. The House askedy to testify on Friday. That seems unlikely. Two other White House aides did not show for their testimony Tuesday. OMB Associate Director for National Security Programs Mark Sandy is also expected to testify on Friday.

Jennifer Williams, But a top adviser to Vice President Mike Pence, is expected to talk to impeachment investigators Thursday. She's a longtime State Department official and was on the July 25 phone call between Trump and Ukraine President Volodymyr Zelensky.

Jim Jordan, a top Trump ally, will likely move a top Trump ally, will likely move temporarily to the House Intelligence Committee , giving the President another key ally in all proceedings.

Department of Justice says in a new memo that witnesses Thesays in a new memo that witnesses must be able to bring a government lawyer . They have, until now, brought only personal attorneys. The idea is that the President must also be represented in the proceedings. It's not clear yet how the House investigators will respond and whether they'll challenge the memo in court.

Lev Parnas, a Giuliani associate who has been arrested on criminal charges, has a Giuliani associate who has been arrested on criminal charges, has started talks with impeachment investigators through his attorney.

What are we doing here?

The President has invited foreign powers to interfere in the US presidential election.

Democrats want to impeach him for it.

It is a crossroads for the American system of government as the President tries to change what's acceptable for US politicians. This newsletter will focus on this consequential moment in US history.