The U.S. House of Representatives plans to hold a formal vote Thursday on the impeachment inquiry against President Donald Trump over his alleged abuses of power while in office.

In a letter explaining the decision, Speaker Nancy Pelosi told House Democrats that she wanted to push back on claims by Trump and Republican lawmakers that the impeachment inquiry is not valid without a floor vote. Sen. Lindsey Graham, a key Trump ally, introduced a resolution last week condemning the inquiry as “illegitimate.”

Speaker Nancy Pelosi statement confirming a formal House vote on the impeachment inquiry: "We will bring a resolution to the Floor that affirms the ongoing, existing investigation that is currently being conducted by our committees as part of this impeachment inquiry." pic.twitter.com/Qlcit8ycZD — Yamiche Alcindor (@Yamiche) October 28, 2019

While Pelosi said Monday that the Trump administration “made up” the argument that the impeachment inquiry is illegitimate, she said she wanted to take the vote to “eliminate any doubt.”

“This week, we will bring a resolution to the Floor that affirms the ongoing, existing investigation that is currently being conducted by our committees as part of this impeachment inquiry, including all requests for documents, subpoenas for records and testimony, and any other investigative steps previously taken or to be taken as part of this investigation,” Pelosi said in the letter.

On Tuesday, the text of the resolution will be introduced. On Wednesday, the House Rules Committee plans to mark up a resolution directing certain committees to continue their ongoing investigations as part of the impeachment inquiry. The full House will then vote on the resolution Thursday.

Congressional Democratic aides said the vote on Thursday is not about formalizing the impeachment inquiry, but rather about affirming the ongoing, existing investigation. They said the vote is about how to proceed with the impeachment inquiry rather than whether to move forward with it.

House Rules Committee Chairman Jim McGovern, D-Mass., said in a tweet that the resolution is meant “to ensure transparency and provide a clear path forward.”

As committees continue to gather evidence and prepare to present their findings, I will be introducing a resolution, which the Rules Committee will mark up this week, to ensure transparency and provide a clear path forward. — Rep. Jim McGovern (@RepMcGovern) October 28, 2019

Pelosi said the resolution “establishes the procedure for hearings that are open to the American people, authorizes the disclosure of deposition transcripts, outlines procedures to transfer evidence to the Judiciary Committee as it considers potential articles of impeachment, and sets forth due process rights for the President and his Counsel.”

A senior White House official told PBS NewsHour that Trump administration officials are waiting to see the text of the resolution because there is concern it might just “provide cover for Democrats” rather than “solve the issues” connected to Republicans’ concerns. The official said Trump and Republicans want Trump to be able to bring in his own lawyers to cross examine congressional witnesses and see evidence in the inquiry.

Still, White House press secretary Stephanie Grisham released a statement soon after the vote was announced saying that Pelosi was essentially caving into Republican demands.

“We won’t be able to comment fully until we see the actual text,” Grisham said in the statement. “But Speaker Pelosi is finally admitting what the rest of America already knew – that Democrats were conducting an unauthorized impeachment proceeding, refusing to give the President due process, and their secret, shady, closed door depositions are completely and irreversibly illegitimate.”

House Democrats launched an impeachment inquiry against the president last month after learning of a phone call in which Trump asked the president of Ukraine to look into former vice president and 2020 hopeful Joe Biden and his son Hunter.