WASHINGTON — What did about three dozen House Democrats do over their summer vacation? They decided they wanted to try to impeach President Trump.

As lawmakers returned to the nation’s capital this week, the addition of those new converts means more than half of the 235 Democrats in the House now support the start of an impeachment inquiry against Trump. Lawmakers said constituents at town hall meetings and other events over the summer break sent a resounding message that they want action and accountability.

“People had a lot of questions, and that is how I ended up making the statement I did,’’ said Representative Lauren Underwood of Illinois, a Democrat who won a traditionally Republican district in the Chicago suburbs last year and came out in support of starting an impeachment inquiry on Twitter late last month.

The House Judiciary Committee this week announced it was ready to amp up its investigation into whether to open a formal inquiry. House Speaker Nancy Pelosi has so far opposed that move, but House Democrats on Tuesday rushed to downplay any signs of a divide over how to proceed, even as time was running out to make a decision.

Massachusetts Representative Bill Keating, who was among the party members who this summer endorsed the start of impeachment proceedings, said Pelosi “was supportive’’ of the Judiciary Committee move during a closed meeting Tuesday morning of House Democrats.

House Judiciary Committee chairman Jerrold Nadler has said his committee will meet Thursday to vote on new procedures for its hearings over whether to recommend the impeachment inquiry. If they’re adopted, as expected, the changes would lengthen the time witnesses can testify, allow the committee to analyze evidence in closed session, and allow Trump to respond to allegations in writing.

House Judiciary member David Cicilline of Rhode Island called the step significant, saying it was the first time the committee would formally consider the question of impeachment and that it was in line with Pelosi’s direction. “The speaker’s position has been the committees must move forward with our oversight responsibilities, that we must follow the facts wherever they take us, and that no one’s above the law,’’ he said.

Pelosi has resisted calls to start an impeachment investigation out of concern that it could backfire politically, given tepid public support and near-solid Republican opposition. A senior staffer with a House Judiciary committee member said Pelosi and Nadler had long been at odds over whether to move forward with the impeachment inquiry and that some within the caucus had grown frustrated with the speaker for not moving more swiftly.

Pelosi has said she wants to make sure all means are exhausted before deciding whether to launch an impeachment inquiry, pointing to pending court cases and at least six ongoing congressional investigations under the Judiciary, Oversight and Reform, and Intelligence committees.

“My position has always been, whatever decision we made in that regard would have to be done with our strongest possible hand, and we still have some outstanding matters in the courts,’’ Pelosi said before the summer break. “It’s about the Congress, the Constitution, and the courts, and we are fighting the president in the courts.’’

Pelosi did not comment to reporters after leaving the meeting of House Democrats Tuesday.

If Democrats don’t launch an inquiry soon, they risk having an impeachment effort spill into next year’s election season. But Representative Ro Khanna, a Democrat from California, said he believes the next three months will provide enough time for committees to dig into the facts.

“We don’t want to politicize this,’’ he said. “We have to pursue it until we get a resolution, but I think it is much better to do this before the Iowa caucuses.’’

At least 134 of 235 House Democrats publicly favor starting the impeachment inquiry, according to a CNN count. Just under 100 Democrats supported an inquiry before the summer recess began.

But most members in favor of the inquiry are from progressive or safe Democratic districts. Members in swing districts were in favor of continuing the ongoing deliberate process outlined by Pelosi.

A Quinnipiac University poll released in late July found that 32 percent of Americans thought Congress should begin the process to impeach Trump, even as his approval ratings have consistently remained low.

Yet the calls for impeachment among House Democrats have grown as the Trump administration has refused to cooperate with congressional investigations, disregarding subpoenas related to providing his tax returns, the unredacted report from former special counsel Robert Mueller, and testimony from former White House counsel Don McGahn.

Before her Twitter statement, Underwood had previously believed people in her district cared more about issues such as health care than impeachment. Now she approved of the Judiciary Committee’s latest move.

“It’s about being deliberate,’’ she said. “And it’s about being diligent to make sure that we are being given all the facts in order to do our jobs to protect our country from this ever happening again.’’

Underwood and some other House Democrats on Tuesday said the questions over impeachment were nonstop during the summer.

“One thing I didn’t hear was that the House shouldn’t be looking into these issues,’’ Keating said. “It is a question of how and what timeline. Those are things that differed among people.’’

It was the kind of groundswell that Democrats had hoped for ahead of long-awaited testimony from Mueller, who days before the summer break appeared before two House committees to explain his investigation into Russian interference in the 2016 election and possible attempts by Trump to hinder the probe. Mueller’s testimony did not produce any bombshells and was seen as underwhelming, but he did confirm that he did not exonerate Trump of obstruction of justice after a two-year investigation.

The House Judiciary Committee vote over its new procedures comes as Corey Lewandowski, Trump’s former campaign manager, is set to testify at a hearing next week.

Nadler said Trump twice asked Lewandowski to deliver a message to former attorney general Jeff Sessions in attempts to limit the Mueller investigation, “making him a critical witness to presidential obstruction of justice.’’

The committee also has subpoenaed former White House aides Rob Porter and Rick Dearborn, whom Nadler said witnessed Trump’s repeated obstruction, to appear at the same hearing.

“The adoption of these additional procedures is the next step in that process and will help ensure our impeachment hearings are informative to Congress and the public, while providing the president with the ability to respond to evidence presented against him,’’ Nadler said this week. “We will not allow Trump’s continued obstruction to stop us from delivering the truth to the American people.’’

Jazmine Ulloa can be reached at jazmine.ulloa@globe.com or on Twitter: @jazmineulloa.