This post has been updated.

The House’s impeachment inquiry of President Trump has entered a new phase, as the House Judiciary Committee conducts its own hearings to decide specifically what might be included in the impeachment articles.

Wednesday’s hearing features a number of experts on impeachment. Below are some big takeaways.

1. A signal that impeachment will include Mueller?

The House Intelligence Committee’s impeachment hearings focused almost exclusively on Ukraine. That was the new information, after all, and that’s what the witnesses could speak to.

But at the start of Wednesday’s hearing, Judiciary Committee Chairman Jerrold Nadler (D-N.Y.) seemed to indicate he was inclined to include something else in the impeachment articles: the obstruction-of-justice portions of the Mueller investigation.

Nadler’s opening statement accused Trump of obstructing both the Ukraine probe and the Russia investigation, and it included plenty on the latter, in a way that suggests it was a calculated choice.

“When his own Justice Department tried to uncover the extent to which a foreign government had broken our laws,” Nadler said of the Russia probe, “President Trump took extraordinary and unprecedented steps to obstruct the investigation, including ignoring subpoenas, ordering the creation of false records, and publicly attacking and intimidating witnesses. Then, as now, this administration’s level of obstruction is without precedent.”

Special counsel Robert S. Mueller III opted not to decide whether Trump had obstructed justice, given Justice Department guidelines that say a sitting president can’t be indicted. But there were five instances in which he suggested there was substantial evidence to support all three criteria for an obstruction charge.

The Washington Post’s Rachael Bade has written about how Democrats were quietly talking about including Mueller in the impeachment articles. Of course, just because Nadler may think that should be included doesn’t mean his fellow Democrats will agree.

2. Professor Pamela Karlan, center stage

Before the hearing began, the committee’s ranking Republican, Rep. Douglas A. Collins (Ga.), was officially passed over for a Senate appointment by Georgia Gov. Brian Kemp (R), who instead picked business executive Kelly Loeffler. Trump had wanted Collins, a fierce defender of the president, to get the seat.

And shortly thereafter, Collins was upbraided by one of the witnesses.

Stanford law professor Pamela S. Karlan noted she had worked with some of the Republicans on the committee, and then addressed Collins directly. She took exception to Collins suggesting the hearings weren’t about the underlying facts and were instead about a political vendetta.

“And here, Mr. Collins, I would like to say to you, sir, that I read transcripts of every one of the witnesses who appeared in the live hearing, because I would not speak about these things without reviewing the facts,” Karlan said. “So I’m insulted by the suggestion that as a law professor, I don’t care about those facts.”

It was a level of combativeness that you rarely see from a witness. And it made Karlan an early focal point of this hearing.

Later on, Karlan made a pointed comment about the powers the Constitution delegates to a president, noting that a key restriction was on titles of nobility.

“So while the president can name his son Barron, he can’t make him a baron,” she said, drawing some laughter.

White House spokeswoman Stephanie Grisham charged that Karlan was using “a teenage boy who has nothing to do with this joke of a hearing (and deserves privacy) as a punchline.” First lady Melania Trump also weighed in.

Karlan apologized later in the hearing. “I want to apologize for what I said earlier about the president’s son,” she said. “It was wrong of me to do that.” She added that she wished Trump would also apologize for the things he’s done wrong.

Rep. Matt Gaetz (R-Fla.) used his time to criticize the comment as well. And he referred to past comments from Karlan in which she said liberals live closer together and that very conservative people tended to spread out, “perhaps because even they don’t want to be around themselves.” Gaetz suggested it showed Karlan’s contempt for conservatives; Karlan said she was merely making a point about how conservatives generally don’t want to live in crowded areas, even if their neighbors are like-minded.

Karlan once told The Washington Post that she would like to have been a Supreme Court justice — “but not enough to have trimmed my sails for half a lifetime.” That sensibility was certainly on display Wednesday.

3. A unique GOP witness — who won’t defend Trump the man

The GOP’s lone witness at the table on Wednesday, George Washington University law professor Jonathan Turley, is a veteran of these hearings. As he noted in his opening statement, he also testified at President Bill Clinton’s impeachment hearings.

And Turley clearly came prepared. His opening statement numbered 53 pages — significantly longer than the other witnesses’ — and contained extensive, detailed footnotes.

Perhaps his strongest argument came at the top, when he said that he has very little regard for Trump, even as he doesn’t believe Trump should be impeached.

“First, I am not a supporter of President Trump. I voted against him in 2016 and I have previously voted for Presidents Clinton and Obama,” Turley said in his written statement. “Second, I have been highly critical of President Trump, his policies and his rhetoric, in dozens of columns. Third, I have repeatedly criticized his raising of the investigation of the Hunter Biden matter with the Ukrainian president.”

Turley even said, contradicting Trump, that Trump’s July 25 call with Ukraine President Volodymyr Zelensky “was anything but perfect.” He added in his written statement that Trump’s “reference to the Bidens was highly inappropriate.” He even admitted the House had a legitimate reason to investigate the Ukraine situation. But he said impeachment wasn’t warranted based on current evidence.

Turley’s advocacy for a president he doesn’t support was a noted contrast to the other three witnesses, all of whom, as the White House quickly noted, had publicly disparaged Trump in the past. Some suggested Democrats should have invited witnesses who didn’t appear so ideologically opposed to Trump.

Turley argued in his briefer verbal statement that impeachment was not a remedy for political anger, nor was it likely to reduce it.

“I get it: You’re mad,” Turley said. “The president’s mad. My Republican friends are mad. My Democratic friends are mad. My wife is mad. My kids are mad. Even my dog seems mad. And Luna is a goldendoodle, and they don’t get mad.”

He added: “So we’re all mad. Where’s that taken us? Will [a] slipshod impeachment make us less mad, or will it only give an invitation for the madness to follow in every future administration?”

Turley did give Democrats some arguments, though, including when he suggested if a Ukraine quid pro quo was directly tied to Trump, it could be impeachable.

“In fact, non-crimes have been part of past impeachments; it’s just that they’ve never gone up alone or primarily as the basis of impeachment,” Turley said. “That’s the problem here. If you prove a quid pro quo, then you might have an impeachable offense.”

4. A curious argument against impeaching Trump

One argument Turley kept coming back to seemed to be one that Republicans will run with, even though it had some key flaws. He repeatedly suggested that this impeachment process would set a record for speed.

“Why do you want to set the record for the fastest impeachment?” he asked the Democrats on the panel. “Fast is not good for impeachment.”

The first issue with this is we’ve had only two impeachments — Bill Clinton and Andrew Johnson — so it’s not like there’s a lot to compare it to.

But the second is that it doesn’t appear to be correct.

It has been 71 days since House Speaker Nancy Pelosi (D-Calif.) announced that the House would begin impeachment proceedings. In the case of Bill Clinton, it was 75 days between the House authorizing the impeachment inquiry and actually impeaching Clinton. There were process differences that make them less directly comparable: The investigative work for Clinton’s impeachment was already done by independent counsel Kenneth Starr, which allowed for the actual impeachment process to move more quickly. And this time, the House waited a month before voting on formalizing the inquiry, though depositions began very quickly after Pelosi’s announcement.

The Johnson example is worse for Turley’s comparison. Johnson was actually impeached just three days after committing the offense for which he was impeached — the removal of Secretary of War Edwin M. Stanton. Johnson removed Stanton on Feb. 21, 1868; he was impeached on Feb. 24; and then the House decided on the actual impeachment articles. It was sent to the Senate by March 4 — less than two weeks after the offense for which Johnson was impeached.

The more valid part of Turley’s argument was that the impeachment hearing is moving faster than the courts, which have become involved in settling the disputes between Congress and the White House. House investigators subpoenaed many executive branch officials and documents, and the White House blocked officials from testifying and didn’t turn over the requested documents, so Congress sued.

Turley pointed out that President Nixon resigned after a Supreme Court decision that found he had to turn over evidence. Turley pointed out that it lent legitimacy that two branches of government trumped the executive.

The issues with it notwithstanding, Republicans like Collins seized on Turley’s argument that the impeachment process is rushed.

5. Nadler under fire

Republicans seem to believe they could make an example of Nadler and use him to argue that this process isn’t fair.

From the outset, they made clear part of their goal Wednesday was to ruffle Nadler. Nadler earned criticism for his committee’s handling of a September hearing with former Trump campaign manager Corey Lewandowski, and Pelosi’s decision to begin the proceedings in the Intelligence Committee, chaired by Rep. Adam B. Schiff (D-Calif.), wasn’t exactly a vote of confidence in Nadler.

Shortly after Nadler’s opening statement, Republicans began peppering him with parliamentary inquiries and made a motion to compel Schiff to testify. Democrats moved to table the motion, and Republicans forced a vote on it. They also asked whether the federal rules of evidence could be enforced in the hearing.

When the first witness, Harvard law professor Noah Feldman, began speaking, Republicans repeatedly asked to be recognized for motions. Nadler said such motions had to wait until after the witnesses’ opening statements. But they kept trying.

When Feldman finished, Republicans moved to postpone the hearing. Democrats again objected, and Republicans forced another roll-call vote.

Through it all, Nadler paused and seemed somewhat uncertain about how to handle it. His halting stewardship of the hearing certainly wasn’t as smooth as Schiff’s. And at the very end, Democrats tried to offer a motion, only to have Nadler -- who was apparently fed up -- declare it to be too late and gavel the hearing to a close. Republicans expressed exasperation. “Typical,” exclaimed Rep. Louie Gohmert (R-Tex.).