After another week trying to contain impeachment talk, House Speaker Nancy Pelosi (D-Calif.) delivered a lecture that was equal parts explanation of constitutional complexities and airing of her own frustrations.

“You get impeached, and it’s an indictment — it’s an indictment. So when you’re impeaching somebody, you want to make sure you have the strongest possible indictment,” Pelosi told reporters Wednesday. The general public, she said, does not understand all the steps it takes to remove a president. “People think all you do [is] vote to impeach, bye-bye, birdie. It isn’t that — it’s an indictment. So you need the best possible indictment.”

And among members of Congress, there seems to be little historical understanding of how quickly things would move if the House voted to begin impeachment — it might be only a matter of weeks before the full House would consider impeaching President Trump.

Pelosi has struggled to explain why she prefers a more methodical pace for the Trump investigations. She has tried to explain, to reporters and Democratic colleagues in private, that it is the only way to build a case strong enough to turn public sentiment sharply enough against Trump, so that Senate Republicans would support his removal from office.

Pelosi’s frustration boiled over during her weekly news briefing, when she accused the media of creating “some entertainment” in reporting on obvious cracks inside the Democratic caucus.

“We’re following the facts. We’ll take them where they lead us. And as we go down that path, we will be as strong as we can be,” Pelosi said, speaking louder for emphasis. “There is no controversy.”

Her latest private clash surrounding impeachment proceedings came Tuesday with five committee chairmen running investigations on Trump, as first reported by Politico. Pelosi snapped at Rep. Jerrold Nadler (D-N.Y.), chairman of the House Judiciary Committee, that she wanted the president “in prison” after he leaves office, not an impeachment that ends in a likely acquittal vote in the Senate.

Those chairmen are being egged on by a small but very vocal contingent of Democrats calling for a much quicker pace. They have dominated the cable airwaves and drawn outsize attention from liberal activists on social media with calls for immediate impeachment proceedings in the Judiciary Committee.

After Pelosi had tamped down impeachment talk in late May, Robert S. Mueller III’s appearance last week at the Justice Department jolted the caucus anew. The now former special counsel explained his investigators would have cleared the president of a charge of obstruction of justice if they felt the evidence was clear — but it wasn’t.

With that came a fresh batch of converts among House Democrats calling for impeachment proceedings. “I think they should begin immediately. I think they should take the course of this summer and then see where we are come September,” Rep. Brendan Boyle (D-Pa.) said this week. He estimated a full House vote could come by October with a Senate trial to follow.

“This would conclude by the end of this calendar year, and that’s well before the presidential election,” said Boyle, who had been previously holding back on impeachment.

There are just two precedents for such actions in the past 100 years, under the presidencies of Richard M. Nixon and Bill Clinton. One resulted in Nixon resigning, forced out by senior congressional Republicans who warned they would vote to remove him. The other resulted in a 50-50 Senate vote, well short of the two-thirds majority required by the Constitution to convict and remove Clinton from office.

The Clinton impeachment moved at warp speed; the Nixon proceedings crawled along for many months.

In the fall of 1998, after the independent counsel report to Congress documented Clinton’s coverup of an extramarital affair, House Republicans moved swiftly. On Oct. 8, less than a month before the midterm elections, the House approved the launch of an impeachment inquiry, a move supported by 31 Democrats.

With hearings starting in mid-November, the Judiciary Committee recommended impeachment less than a month later, and the full House approved two articles against Clinton on Dec. 19, 1998.

The Senate trial lasted five weeks, pausing most days to simultaneously work on legislation. It ended in the deadlocked vote of Feb. 12, 1999 — barely more than four months after the initial House vote. And everything would have moved faster if not for congressional recesses so lawmakers could return home for campaigning and the holidays.

Today’s Democratic impeachment chorus wants to avoid that example.

“I want a legitimate, real process that would last several months. I look at 1998 as the cautionary tale of exactly what not to do,” Boyle said.

But Democrats supporting Pelosi’s go-slow approach believe that today’s political environment will not allow for the meticulous process of 45 years ago once the House casts a formal vote to start impeachment proceedings — the genie will be out of the bottle, and liberal activists will demand immediate action.

That’s what Pelosi tried to explain Wednesday. “We know exactly what actions we need to take, and while that may take more time than some people want it to take, I respect their impatience,” she said.

In early 1974, House Democrats moved more methodically against Nixon. By July 1973, the president had already refused subpoenas from the Senate Watergate Committee for secret White House recordings, which were revealed during committee hearings. And in October that year, Nixon fired the top two Justice Department officials for refusing his demand to oust a special prosecutor.

Within two weeks of the “Saturday Night Massacre,” the Judiciary Committee put in place staff to oversee the investigation of Nixon and prepare for the possibility of impeachment.

The full House did not vote to start an impeachment inquiry until Feb. 6, 1974, and even then the Judiciary Committee spent more than two months compiling evidence, issuing subpoenas, reviewing materials and preparing witnesses.

Once the committee formally opened public hearings, on May 9, 1974, the process took off, and 11 weeks later the panel reported out three articles of impeachment against Nixon. He announced the night of Aug. 8 that he would formally resign the next day.

Pelosi has for months explained her opposition to impeachment and asserted that Trump is baiting Democrats into a Clinton-style impeachment on party lines, in a bid to boost his reelection chances.

This week, again trying to hold back impeachment forces, she tried to at least steer those Democrats toward a process more closely resembling Nixon’s implosion.

“Make no mistake: We know exactly what path we are on,” she said Wednesday.