WASHINGTON — If you thought the political news was already intense, dizzying and historic, brace yourself for what’s happening today.

Beginning at 9:00 am ET on Capitol Hill, E.U. Ambassador Gordon Sondland testifies in the impeachment probe — the most highly anticipated public hearing yet in the proceedings.

Then, at 2:30 pm ET, Laura Cooper of the Defense Department and David Hale of the State Department have their turns before the House Intelligence Committee’s impeachment inquiry.

And at 9:00 pm ET from Atlanta, 10 Democratic presidential candidates — Joe Biden, Elizabeth Warren, Bernie Sanders, Pete Buttigieg, Kamala Harris, Andrew Yang, Amy Klobuchar, Tulsi Gabbard, Cory Booker and Tom Steyer – participate in the fifth round of Dem debates, this one hosted by MSNBC and the Washington Post.

Phew.

Sondland’s testimony is significant because it comes after the State Department’s David Holmes revealed behind closed-door testimony that he overheard a phone conversation between the E.U. ambassador and President Trump, in which the two men discussed “the investigation” — ostensibly into Joe Biden.

“I then heard President Trump ask, quote, ‘So he’s going to do the investigation?’ unquote. Ambassador Sondland replied that, ‘He’s going to do it,’ adding that President Zelensky will quote, ‘Do anything you ask him to,’” Holmes told investigators.

More from Holmes after that call: “I asked Ambassador Sondland if it was true that the president did not give sh&t about Ukraine. Ambassador Sondland agreed that the president did not give a sh-t about Ukraine. I asked why not, and Ambassador Sondland stated, the president on cares about, quote, unquote, big stuff… Ambassador Sondland replied that he meant, quote, unquote, big stuff that benefits the president, like the quote, unquote, Biden investigation that Mr. Giuliani was pushing.”

Does Sondland confirm the details of that phone conversation, which he didn’t disclose in his earlier testimony?

If so, it would be the first testimony directly tying the president of the United States to the effort asking Ukraine to investigate the Bidens — outside of the partial transcript of that July 25 call, of course.

Sondland, if you’ll recall, already revised his testimony once before when he admitted that suspended aid to Ukraine had become linked to the country’s “proposed anti-corruption statement.”

Today’s a big day, and we’ll likely know just how big by about 10:00 am ET or 10:30 am ET this morning.

What we learned during yesterday’s testimony

If Kurt Volker and Tim Morrison were supposed to be the best witnesses yet for the GOP, what does that say about where Republicans stand when it comes to the substance in the impeachment inquiry?

Here are some of the highlights from yesterday’s testimony:

Kurt Volker, the former U.S. special envoy to Ukraine: "I have learned many things that I did not know at the time of the events in question," he said in his opening statement. "I did not know of any linkage between the hold on security assistance and Ukraine pursuing investigations. No one had ever said that to me — and I never conveyed such a linkage to the Ukrainians."

Democratic attorney Daniel Goldman: “What did ambassador Sondland tell you that he told Mr. Yermak [an aide to Ukraine’s president]?"

Former National Security Council official Tim Morrison: “That the Ukrainians would have to have the prosecutor general make a statement with respect to the investigations as a condition of having the aid lifted.”

Lt. Col. Alexander Vindman: "I was concerned by the [July 25] call, what I heard was inappropriate."

Vice-presidential aide Jennifer Williams: Said she "found the July 25th phone call unusual because, in contrast to other presidential calls I had observed, it involved discussion of what appeared to be a domestic political matter."

Data Download: The number of the day is … 20

That’s the estimated number of hours of public testimony so far in the impeachment probe, according to NBC’s Capitol Hill team.

As of the end of Tuesday, seven different witnesses have testified before the House Intelligence Committee for roughly 20 hours.

That number, of course, will only increase after today’s testimony.

2020 Vision: The Democrats went down to Georgia

In addition to today’s big testimony on Capitol Hill, the Democratic presidential candidates will be participating in their fifth round of debates tonight from Atlanta.

MSNBC and the Washington Post are hosting the debate, which takes place at 9:00 pm ET, and the moderators are MSNBC’s Rachel Maddow, NBC’s Andrea Mitchell, NBC’s Kristen Welker and the Washington Post’s Ashley Parker.

The previous Democratic debates have brought us different frontrunners. In June and July, Joe Biden was the overwhelming frontrunner.

In September and October, Biden shared that frontrunner status with Elizabeth Warren.

And for tonight, you can argue that there’s a Big Four of frontrunners — Biden, Warren, Pete Buttigieg (who’s been leading in the Iowa polling) and Bernie Sanders.

On the campaign trail today

The fifth round of Democratic debates takes place in Atlanta beginning at 9:00 pm ET…. Julián Castro, who isn’t participating in the debate, holds a housing roundtable in Atlanta… Deval Patrick, who also isn’t participating, is in South Carolina… And on the GOP side, Bill Weld stumps in New Hampshire.

Dispatches from NBC’s campaign embeds

Joe Biden picked up his 19th congressional endorsement, per NBC’s Marianna Sotomayor. The Biden campaign released the following information about Oregon Congressman Kurt Schrader’s endorsement: Schrader “represents the kind of geographically diverse swing district that will be key to winning the presidency in 2020.” Schrader, in his endorsement said, “Two things matter most in this election — beating Donald Trump, and getting things done in his wake – and Joe Biden is the one candidate with the experience and heart needed to do them both. I know that Joe can win in tough districts all across this country, giving Democrats a lift up and down the ballot. And once in office, Joe is the one candidate who has what it takes to work with the other side to get real things done.”

And Stacey Abrams spoke at a roundtable about voter suppression in Georgia, ahead of the Democratic debate. Per NBC’s Priscilla Thompson opened her speech quipping, “My name is Stacey Abrams and I am not the governor of Georgia." Thompson reports, “She emphasized the importance of accessibility to the ballot for all types of voters. ‘Our accessibility has to be more than lip service and it has to be more than a website,’ she said. ‘It has to be real.’”

Tweet of the day

Mark Meadows just went "off the record" with a bunch of reporters live on C-SPAN, so that's how things work here in DC. — Derek Willis (@derekwillis) November 19, 2019

ICYMI: News clips you shouldn’t miss

The New York Times previews Ambassador Gordon Sondland's testimony and the discrepancies between his previous testimony and what the House has heard from other witnesses.

Mayor Pete Buttigieg's quick rise at the polls makes him an obvious target for other Democrats on Wednesday's debate stage, Politico reports.

Here are 10 takeaways from Tuesday's impeachment hearings.

President Trump blasted the media for speculation that his recent trip to Walter Reed was anything more than a routine visit.

The State Department is denying a Time Magazine report that Secretary of State Mike Pompeo is looking toward the door.

Trump Agenda: Mixing personal with business

Democrats are pushing the State Department to investigate the use of personal cell phones by Trump officials conducting official business.

While President Trump recently ordered the Navy to promote a SEAL who posed with an ISIS fighter's corpse, the Navy is discussing expelling him from the SEAL corps.

Two U.S. service members died in Afghanistan on Wednesday after a helicopter crash.

The New York Times profiles Wisconsin Sen. Ron Johnson's in light of his defense of President Trump on impeachment and his Ukraine expertise.

2020: It’s good not to be the sole frontrunner

As Democrats duke it out, Joe Biden has received a brief respite from the thunder dome.

Here's what issues got the most time during the past Democratic debates.

Meet the Nevada DREAMer that Democratic candidates all want to meet with.