The impeachment inquiry could be formalized following a vote in the House on Thursday, after weeks of closed door hearings and testimonies.
House Speaker Nancy Pelosi on Monday unveiled plans to formally open the ongoing impeachment proceedings against President Donald Trump, in a letter to Democrat lawmakers saying she wanted to challenge suggestions that the ongoing inquiry "lacks the necessary authorization."
The decision by House Democrats to bring forward a resolution this week to "affirm" impeachment proceedings will lead to deposition transcripts and inquiry hearings being "open to the American people," according to Pelosi's letter.
The House Speaker initially announced the impeachment inquiry on September 24 after a whistleblower raised concerns about a July phone call between the commander-in-chief and Ukrainian President Volodymyr Zelenskiy.
A transcript of the call released by the White House showed that Trump urged Zelenskiy to investigate a potential political rival, former Vice President Joe Biden.
Military aid to the country was withheld around this time, in what is alleged to have been a quid pro arrangement, although the president has insisted there was no pressure or quid pro quo discussed. The funds were later released.

The president and his Republican supporters on Capitol Hill have long denied the accusations and sought to discredit the inquiry, with Trump calling the impeachment process a "scam" as he addressed the International Association of Chiefs of Police in Chicago on Monday.
House Republicans also went through with a stunt last week that saw a number of them attempt to storm a secure room where closed door impeachment inquiry hearings have been held. They said their stunt was a protest against the "secrecy" of the process.
In her letter to Democratic lawmakers yesterday, Pelosi pitched the resolution to formalize the impeachment inquiry as a rebuke to those Republican attempts to pour cold water on proceedings.
When is the vote to formalize impeachment?
The House vote to formalize its impeachment inquiry against President Trump will take place in the Capitol on Thursday.
Rep. Jim McGovern, the chairman of the House Rules Committee, has promised to introduce a resolution "ensuring transparency and providing a clear path forward" for the impeachment inquiry today and said he aims to "markup" the resolution on Wednesday at 3 p.m. ET.
How many votes are needed for the impeachment inquiry formalization to pass?
A simple majority in the House of 218 votes will lead to the impeachment inquiry becoming formal. Democrats hold a majority, with 234 seats in the House, which is made up of 435 representatives, so it is unlikely that the inquiry will not be formalized.
What happens next?
If the House votes to formalize the impeachment inquiry, Speaker Pelosi has said inquiry hearings will be opened up, testimony transcripts released and evidence handed to the House Judiciary Committee so it can draft articles of impeachment.
"We are taking this step to eliminate any doubt as to whether the Trump administration may withhold documents, prevent witness testimony, disregard duly authorized subpoenas or continue obstructing the House of Representatives," Pelosi said in a letter to congressional Democrats.
Newsweek has contacted the White House asking what it plans to do in the event of the impeachment inquiry being formalized, but had not heard back at the time of publication.
How impeachment works
The House Judiciary Committee will look over accusations and craft articles of impeachment following the inquiry.
If the proposed articles get through the committee after a simple majority vote, the House only needs to reach the same simple majority if it wishes to back the articles and send them to the Senate—a highly likely outcome given that Democrats hold a majority of seats in the House.

The Senate will then draw up a bill of indictment and hold a trial of President Trump, with senators making up the jury. A two-thirds majority vote is then required for the commander-in-chief to be convicted and removed from office.
Precedent dictates that the Senate may be unwilling to convict and remove Trump from office, given that the chamber is controlled by Republicans who are largely reluctant to back the impeachment inquiry.
However, Trump has long struggled to gain a foothold in certain strands of the GOP and may find his colleagues (particularly those in swing seats) unwilling to stake their own careers on protecting him—particularly given the increasing public support for the impeachment inquiry.