US lawmakers are scheduled on October 31 to cast their first vote in the impeachment investigation of President Donald Trump as the Democratic-controlled House of Representatives takes up a measure that sets up the next steps in the fast-moving effort.
The vote will be the first formal test of support for the inquiry. Democrats, who control 224 seats in the 435-seat chamber, need a simple majority to approve the resolution.
The measure calls for public hearings and the release of transcripts from closed-door proceedings. It also outlines what rights Republican lawmakers and Trump himself would have to participate as the process moves ahead.
Republicans have accused Democrats of trampling on Trump's rights and keeping the process too secret.
The U.S. Constitution gives the House broad authority to set the ground rules for an impeachment inquiry and Democrats say they are following House rules on investigations. They have promised to hold public hearings on the case against Trump.
Lawmakers leading the investigation also plan to hear closed-door testimony from Tim Morrison, the top Russia specialist on Trump's National Security Council. Morrison resigned from his position on Wednesday, a senior administration official said.
Members of the three committees conducting the investigation expect Morrison to fill in more of the details about Trump's dealings with Ukraine. As someone directly involved in the negotiations, Morrison's testimony could combat charges by Trump's fellow Republicans that the inquiry to date has largely relied on second-hand accounts.
Committee members have asked a far more prominent player, former national security adviser John Bolton, to appear next week. Others have testified that Bolton was alarmed by a White House effort to pressure the president of Ukraine to investigate Trump's political rivals.
If the House pursued impeachment, it would require a simple majority in the 435-member House to trigger a trial in the Republican-controlled Senate. Conviction requires the support of a two-thirds majority in the 100-member body.
The impeachment inquiry focuses on a July 25 telephone call in which Trump asked Ukrainian President Volodymr Zelenskiy to investigate Democratic political rival Joe Biden, a former U.S. vice president, and his son Hunter, who had served as a director for Ukrainian energy company Burisma. Trump has denied wrongdoing and called the inquiry a sham.
The investigation is probing whether Trump misused the power of his office for personal political gain and, if so, whether that rises to the level of "high crimes and misdemeanours" that merit impeachment and removal from office under the Constitution.
Trump made his request to Zelenskiy for an investigation into the Bidens after withholding $391 million in security aid approved by Congress to help Ukraine fight Russian-backed separatists in eastern Ukraine. Zelenskiy agreed to Trump's requests. The aid was later provided.
Also on Thursday, a federal judge in Washington will hear arguments as Democrats seek to force former White House counsel Don McGahn to testify about Trump's efforts to undermine Special Counsel Robert Mueller's investigation into Russia's interference in the 2016 presidential election.