It's a coincidence to make your head spin. On the same day Trump teases that he might testify before the impeachment inquiry, House Democrats make clear they are investigating Trump for lying to Mueller's Russia investigation.

Trump teased testimony for Mueller too.

Remember, there was a long tease as to whether Trump would submit to an actual deposition with Mueller. It was not unlike what he started doing today with Pelosi. But ultimately he answered questions in writing.

What's this investigation, again?

This is quite separate from the impeachment inquiry, but they could ultimately fuse together. This is an investigation by House Democrats into whether Trump obstructed the Russia investigation. They said at a court hearing Monday that they want to determine if Trump was telling the truth when he said he couldn't recall discussing WikiLeaks with Roger Stone, his friend and informal political adviser, who was convicted on Friday of lying to Congress.

What did Trump tell Mueller?

Trump told Mueller, in writing, that he had no recollection of talking to Stone about WikiLeaks.

What did Gates and Manafort tell Mueller?

That could be at odds with testimony by his former deputy campaign chairman Rick Gates, who testified that Trump and Stone did discuss WikiLeaks when Stone was attempting to get secret details about stolen Democratic documents WikiLeaks had.

Gates' former boss, former Trump campaign chairman Paul Manafort, also seems to have told the Mueller grand jury what Trump's approach to WikiLeaks had been in 2016, according to the Mueller report.

But the material was redacted in the released Mueller report by the Justice Department. And Congress wants to see it. Which is why it's in court.

We keep learning new things about the Mueller investigation

In fact, we learned a lot about Mueller's investigation from testimony in the Stone trial. Here's a list of tidbits compiled by CNN's Marshall Cohen and Katelyn Polantz, including that the 10% of the report the Justice Department redacted includes some very important material

In terms of Stone's cooperation with WikiLeaks, the contacts between Trump aides and Russia, and now his pressure on Ukraine, you certainly can see a clear pattern in how elections are viewed in Trump's orbit.

The impeachment inquiry vs. the Mueller probe

The differences between Mueller's methodical by-the-books investigation and its subsequent report could not be more different from the impeachment inquiry. Mueller tried to avoid the appearance of a political motivation at all costs. Democrats are essentially embracing it.

Mueller conducted a thorough, methodical and secret investigation. Details would seep out as he filed criminal charges or announced plea deals with former Trump aides, but the main thrust and his conclusions were hidden from view.

An investigation in public and in real time

The impeachment probe is being conducted in real time and, despite Republican complaints to the contrary, in full view. Democrats are pushing an aggressive timeline to get impeachment done. They're cramming witnesses onto panels for public hearings.

"Saturday Night Live" compared it to a soap opera, but it's really more of a reality TV show.

The American public is learning about new leads at the same time as impeachment investigators.

At the end, there won't be a report for the Department of Justice to review and redact, but rather articles of impeachment for lawmakers to approve or oppose.

Why it's so hard to prove a lie in Washington

I guest-hosted the Impeachment Watch podcast today and Alex Marquardt and I spent a lot of time asking Michael Zeldin, who has been a defense attorney and worked at the Justice Department, about truth and lies in congressional testimony.

What would it actually mean if Trump lied to Mueller and what would happen as a result?

Even if the Department of Justice didn't have a policy of not indicting a president, perjury in a case like this would be really hard to prove in a court of law.

Zeldin pointed out Trump has a lot of wiggle room in the way he answered questions for Mueller. He said he didn't recall rather than that he did not discuss WikiLeaks, for instance. The President can always have his memory jogged, ala Gordon Sondland, who now remembers giving a sort of ultimatum about military aid to Ukrainians.

It will be interesting to see if Sondland's memory is further jogged when he testifies in public on Wednesday now that there's testimony from a State Department staffer at the US Embassy in Ukraine that Sondland had talked on the phone to Trump about Ukrainian President Volodymyr Zelensky and investigations while eating with staffers at a restaurant in Ukraine. Will he now remember that?

Breaking tonight: 2 more transcripts released

Holmes, who says he overheard the call that Sondland placed to Trump at the restaurant in Kiev, testified, "I've never seen anything like this."

Also breaking tonight: Trump aides eye moving impeachment witnesses out of the White House

CNN's Pamela Brown and Kevin Liptak report that Trump aides have explored moving some impeachment witnesses who are on loan to the White House from other agencies, such as Lt. Col. Alexander Vindman, back to their home departments ahead of schedule, according to people familiar with the conversations.

With these bureaucrats taking center stage on his television screen, Trump is asking anew how witnesses such as Vindman and Bill Taylor came to work for him, according to people familiar with the matter. He has suggested again that they be dismissed, even as advisers warn him that firing them could be viewed as retaliation -- a no-no.

What to watch Tuesday

Set to testify:

Jennifer Williams, an aide to Vice President Mike Pence. Closed testimony transcript.

Kurt Volker, the former US special envoy to Ukraine. Closed testimony transcript.

Tim Morrison, the top Russia and Europe adviser on the National Security Council. Closed testimony transcript.

CNN's Manu Raju reports that during Vindman's closed deposition last month, House Intelligence Chairman Adam Schiff, a California Democrat, objected to a line of questioning that he believed was part of a GOP effort to out the whistleblower as Republicans were asking who Vindman had spoken to.

CNN asked Rep. Jim Jordan if the Republicans would go that route again, and he indicated it hadn't been decided yet.

"We are working on what we are going to ask," the Ohio Republican told CNN. "Mr Vindman has been subpoenaed by Congress. That means members of Congress should get to ask the questions they want. Adam Schiff doesn't just get to ask the questions he wants."

Jordan added: "Whether that comes up tomorrow or not — we are still talking about the sequencing of questions and what those questions will be."

Still waiting for Bolton

We will hear Tuesday from Tim Morrison, who replaced Fiona Hill on the National Security Council and will testify alongside Volker. Morrison said John Bolton had a private meeting with Trump in August about the Ukraine aid. Read Morrison's closed-door testimony

It's still not clear when or if Bolton himself will testify, even as it becomes more apparent that he could be a key figure in the story since he may have tried to subvert Trump's shadow foreign policy in favor of the direct and official one.

Bolton wants a court to tell him whether he should respect Trump's executive privilege or a House request that he testify. Bolton was not subpoenaed as part of the impeachment probe since Democrats have suggested they don't want to engage in time-consuming court fights to compel testimony from unwilling officials.

Mike Pompeo was asked to defend his ambassadors from Trump. He did not.

CNN's Jennifer Hansler reports from Foggy Bottom that Secretary of State Mike Pompeo declined to specifically lend his public support to former US Ambassador to Ukraine Marie Yovanovitch and to Bill Taylor, who's now the top diplomat in Ukraine, instead voicing support for the Trump administration's Ukraine policy and again erroneously accusing the Obama administration of allowing Russian President Vladimir Putin to annex Crimea. Pressed again, Pompeo voiced support for the State Department writ large, saying, "I always defend State Department employees. It's the greatest diplomatic corps in the history of the world. Very proud of the team."

Doesn't have anything to say

"Do you agree with the President's tweet on Yovanovitch?" he was asked. (Trump attacked her on Twitter while she was testifying on Capitol Hill last week).

"I don't have anything to say," he said. "I'll defer to the White House on particular statements and the like. I don't have anything else to say about the Democrats' impeachment proceeding. If somebody else has a substantive question about something that the world cares deeply about, I'm happy to take it."

6,286 impeachment ads on Facebook

CNN's Donie O'Sullivan reports that Trump's reelection campaign spent as much as $1 million on Facebook ads mentioning impeachment during the first week of public hearings in the inquiry, according to an analysis of ad data.

The campaign ran 6,286 ads mentioning impeachment from November 11 to Sunday, according to data analyzed by Laura Edelson, a researcher at New York University's Tandon School of Engineering. According to Edelson, the cost of the buy was between $300,000 and $1 million.

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.