WASHINGTON — Progressive groups are expressing “deep disappointment” over House Democrats’ unwillingness to start impeachment proceedings against President Donald Trump and are calling on Speaker Nancy Pelosi to act, according to a letter obtained by The Associated Press.

The groups said in a letter being released Tuesday that voters gave Democrats control of the House “because they wanted aggressive oversight of the Trump administration.”

They said: “The Trump era will be one that evokes the question — what did you do? We urge you to use your power to lead and to stop asking us to wait.”

Pelosi has been reluctant to launch impeachment proceedings, despite growing numbers of Democrats saying it’s time to start a formal inquiry. She says impeachment requires more public support and would detract from the legislative agenda.

Instead, House Democrats are conducting dozens of investigations of the Trump administration , announced a series of new hearings and promised a vote next week to hold Attorney General William Barr and former White House Counsel Don McGahn in contempt of Congress for failing to comply with subpoenas.

But the groups, whose members include millions of Americans, say those being hurt by the Trump administration’s policies and behavior don’t have the privilege of waiting.

“There are people who feel Trump’s boot on their necks every single day,” said Heidi Hess, co-director at CREDO Action. “We expect moral leadership from you.”

The groups signing onto the letter to Pelosi include Indivisible and Democracy for America.

“As Speaker of the House, you have the power to ensure Congress exercises its constitutional obligation to hold this president accountable,” the groups wrote.

“The Trump era will be one that evokes the question — what did you do? We urge you to use your power to lead and to stop asking us to wait.”

Lawmakers returned Monday to Washington after hearing mixed messages from voters at town halls back home. In more liberal districts, voters were quick to discuss impeachment. But in some conservative areas, it hardly came up at all as voters focused on health care, the economy and other issues.

Rep. C.A. Dutch Ruppersberger, D-Md., told reporters Monday it’s most important is to assemble “all the facts and data.”

If Trump refuses to cooperate, “then we might not have any alternative other than to impeach,” he said. “But that’s a long process.”

Amid rising calls for action, Majority Leader Steny Hoyer announced the House will vote next week to hold Barr and McGahn in contempt for their failure to comply with the subpoenas.

Hoyer said the administration’s “systematic refusal to provide Congress with answers and cooperate with congressional subpoenas is the biggest cover-up in American history.”

The resolution scheduled for a June 11 vote will allow the Judiciary Committee to seek court enforcement of its subpoenas. Barr has refused to turn over an unredacted version of special counsel Robert Mueller’s Russia report. McGahn has been directed by the White House to defy the subpoena requests.

Trump has called Mueller’s Russia investigation a “witch hunt” and has declared he “did nothing wrong.”

At a leadership meeting late Monday, some Democrats indicated they welcomed the contempt vote, according to people familiar with the private session.

Earlier Monday, Judiciary Committee Chairman Jerrold Nadler said that his panel will launch a series of hearings on “the alleged crimes and other misconduct” in Mueller’s report as Democrats try to keep the public’s focus on his findings in the Trump-Russia investigation.

The hearings will serve as a stand-in of sorts for Mueller, who said last week he would prefer not to appear before Congress and would not elaborate on the contents of his report if he were forced to testify.

The first hearing, on June 10, looks at whether Trump committed obstruction of justice by intervening in the probe. It will feature John Dean, a White House counsel who helped bring down Richard Nixon’s presidency, though he served a prison term for obstructing justice.

Democrats have suggested they will compel Mueller’s appearance if necessary, but it’s unclear when or if that will happen. Negotiations over Mueller’s testimony are ongoing.

Republicans criticized the decision to hold hearings, with North Carolina Rep. Mark Meadows calling the move “another openly desperate move to resuscitate a dead collusion conspiracy.”

Mueller’s report did not establish a criminal conspiracy between Russia and the Trump campaign to sway the outcome of the 2016 presidential election for Trump. But the special counsel reached no conclusion on whether the Republican president acted illegally to obstruct the probe, saying if the investigators could have cleared Trump of wrongdoing they would have.

Associated Press writer Alan Fram contributed to this report.