The number of House Democrats who back an impeachment inquiry into President Donald Trump hit 123 this week, after Maryland Democrat Rep. Anthony Brown became the latest to join the call.

“Congress and the American people must have a full, unimpeded investigation into the alleged instances of obstruction of justice, public corruption, and other abuses of power by President Trump,” Brown tweeted Friday.

“I fully support the House Judiciary Committee’s formal inquiry into whether to recommend impeachment of President Trump, and I know they will continue to do the hard work to protect our democracy, constitution, and the American people,” he added.

I fully support the House Judiciary Committee’s formal inquiry into whether to recommend impeachment of President Trump, and I know they will continue to do the hard work to protect our democracy, constitution, and the American people. — Anthony Brown (@RepAnthonyBrown) August 16, 2019

Brown’s call made it a total of four Democrats who joined the call for Trump’s impeachment this week, while lawmakers are back home in their districts. Democrat Reps. Deb Haaland (NM), David Price (NC), and Ro Khanna (CA) all said they supported an impeachment inquiry.

House Judiciary Committee Chairman Jerry Nadler (D-NY) this week insisted his investigation into whether Trump obstructed justice and should be impeached constituted a “formal impeachment proceedings” — although an impeachment inquiry normally does not begin without a full vote in the House, which has not yet happened.

Nadler and others have expressed hope that launching the investigation would give his committee leverage when seeking information from the Trump administration in court, since the White House has argued Congress is doing so without a legislative purpose.

According to a whip list maintained by Axios, Brown’s support brings the number of those calling for impeachment to 123 Democrats and one independent — Rep. Justin Amash (MI).

While more than half the Democrat caucus is now calling for an impeachment, Democrats still need 94 more to join the call to reach a majority in the House and begin formal impeachment proceedings.

According to Axios’ count, there are 113 Democrats who have not said where they are on the issue or oppose impeachment. Dozens of Democrats are in vulnerable seats in 2020, according to the Cook Political Report, and the most vulnerable have not supported impeachment efforts to date.

The question remains as to what would drive further calls for impeachment the same way Mueller’s investigation or report did.

Before the Mueller report was made public in April 2019, only 13 Democrats had called for impeachment. After Mueller’s report was released, 81 more Democrats did so over the course of four months. After Mueller’s hearing — which was widely panned as a flop — 30 more Democrats have joined the call.

Nadler said the Judiciary Committee will begin hearings in the fall and make a decision to refer articles of impeachment to the full House by the end of the year.

It is not clear who they may have testify. The Committee has subpoenaed former White House Counsel Don McGahn and recently filed a lawsuit against the administration to force his appearance. It has more recently subpoenaed Trump’s former campaign manager Corey Lewandowski to testify.

The Committee suffered a setback to its strategy of using an impeachment inquiry as leverage in court. An Obama-appointed judge, Judge Beryl Howell, recently rejected a committee request that the same judge be assigned the McGahn lawsuit and a separate lawsuit to seek grand jury information from the Mueller investigation since they both had to do with an impeachment inquiry. The judge said the two were not sufficiently linked.

To date, House Speaker Nancy Pelosi (D-CA) has opposed beginning impeachment proceedings until there was enough evidence to convince the Senate as well as the American public of impeaching Trump. The American public is deeply divided on the issue of impeachment.