The wave sparked by the #MeToo movement caused three members of Congress to step down last week. Now the tide appears to be coming for President Donald Trump.

On Monday, a group of 54 female Democratic Congress members sent a formal letter to the chair of the House Oversight Committee, asking for an investigation into the multiple allegations of sexual assault and harassment against the president.

“In the time of ‘Me Too,’ women across the country are coming forward with their own harrowing stories of sexual harassment and assault,” the letter from the Democratic Women’s Working Group reads. “Members of Congress have also come under scrutiny and investigation, with some resigning, for improper sexual conduct. We cannot ignore the multitude of women who have come forward with accusations against Mr. Trump. With that said, the President should be allowed to present evidence in his own defense.”

Later in the afternoon, the Women’s Working Group issued an update, saying that because of exploding interest in the issue, they were opening up the letter to all Democratic members of the House.

“At this time, more than 100 Democratic members have signed, and more are expected to join the effort,” the group said in a statement.

The letter comes amid renewed focus into the numerous allegations against Trump. In October 2016, a recording of Trump bragging about grabbing women inappropriately and without permission surfaced.

At the time, Trump admitted the tape was real but dismissed it as “locker room talk.” But that didn’t stop more than a dozen women from coming forward to say Trump had touched or kissed them without asking, or made inappropriate, often sexual, remarks. On Monday morning, three of Trump’s accusers — Samantha Holvey, Rachel Crooks, and Jessica Leeds — appeared on the Today show with Megyn Kelly and later held a press conference, calling on Congress to investigate the president.

At the press conference, Crooks stated that lawmakers ought to “put aside their party affiliations and investigate Mr. Trump’s history of sexual misconduct.”

On the Today show, Holvey said she and other accusers were inspired by the #MeToo movement to try again.

“For us to put ourselves out there to try to show America who this man is, and especially how he views women, and for them to say, ‘Meh, we don’t care,’ it hurt,” Holvey told Kelly. “And now it’s just like, all right, let’s try round two. The environment’s different. Let’s try again.”

“For us to put ourselves out there to try to show America who this man is and especially how he views women and for them to say ‘Eh, we don’t care,’ it hurt. Trump accuser Samantha Holvey on @MegynTODAY pic.twitter.com/BIWZCYlQzA — TODAY (@TODAYshow) December 11, 2017

The #MeToo movement of women speaking out about powerful men sexually harassing or assaulting them has already had drastic consequences for three members of Congress. Sen. Al Franken (D-MN), Rep. John Conyers (D-MI), and Rep. Trent Franks (R-AZ) all said they would resign in the past week amid sexual misconduct claims from multiple women.

Now the focus is once again on the president’s words and actions. The White House has continued to assert that all these women are lying — with Trump even privately promoting a conspiracy theory that it wasn’t him on the tape. (It was.)

On Monday, White House press secretary Sarah Huckabee Sanders said there were “eyewitness accounts” that could discredit the allegations of Trump’s accusers, but did not elaborate on what those accounts were.

“In terms of the specific eyewitness accounts, there have been multiple reports; I’d be happy to provide them to you after the briefing is completed,” Huckabee Sanders said.

A congressional hearing could compel testimony from witnesses

In a Republican-led Congress that needs Trump on their side to pass tax reform and other policy changes, there’s currently little appetite for a congressional hearing on the allegations against him. But the number of Democratic voices calling for a hearing is growing.

In addition to yesterday’s letter, there are now six senators calling for the president to resign over the sexual misconduct allegations: Sen. Kirsten Gillibrand (D-NY), Sen. Mazie Hirono (D-HI), Sen. Cory Booker (D-NJ), Sen. Ron Wyden (D-OR), Sen. Jeff Merkley (D-OR) and Sen. Bernie Sanders (I-VT).

Gillibrand, who recently drew attention for her comments that former President Bill Clinton should have stepped down during his own sexual misconduct scandal in the 1990s, has called for a congressional investigation if Trump doesn’t resign immediately.

Wyden and Hirono reiterated Gillibrand’s call on Tuesday.

“Anybody accused of this level of harassment by this many people who refuses to take responsibility ought to be subject to an investigation,” Wyden said. “Nobody’s above the law.”

Hirono was blunter.

“He’s had multiple allegations of sexual assault and he’s an admitted sexual predator,” she said. “I think that attack on Kirsten Gillibrand is yet another example of misogyny and how he attacks everybody who he doesn’t agree with. We don’t need a president like that.”

Asked if she supported impeachment proceedings, Hirono said that process needs to start with Republicans in the House of Representatives.

“I don’t see them moving in that direction and impeachment has to start in the House, which is definitely controlled by Republicans,” she said. “I call on them to be decent and do the right thing for a change.”

As Vox’s Matt Yglesias recently wrote, most of the investigations of Trump’s misconduct so far have come from journalists. But congressional committees have powers that journalists do not; namely, they can issues subpoenas that compel witnesses to talk. Yglesias continued:

Perhaps more importantly, Congress is uniquely situated to clarify the potential illegality of NDAs that purport to prevent current and former employees from discussing misconduct, and to alter federal law, if necessary, to allow people who’ve worked for Trump in the past to answer questions honestly. Either way, there’s simply no need for Congress to continue acting as if there’s nothing to do here except throw up our hands in indecision. Allegations of sexual harassment against members of Congress have prompted calls for Ethics Committee investigations, and in the past, oversight of the executive branch has been considered a core function of the legislative branch.

The calls from Democrats to investigate Trump’s conduct are growing. The question now is whether Republicans will heed those calls.