Millions of Americans are expected to tune into TV screens on Wednesday as the first public hearings in the impeachment inquiry into US president Donald Trump get under way.
It is only the fourth time in history that a US president has been faced with impeachment.
At the heart of the investigation is the "favour" sought by Trump from his Ukrainian counterpart, Volodymyr Zelenskiy, in a phone call on July 25th, in which the US president asked for an investigation into former Democratic vice-president Joe Biden and his son Hunter, who sat on the board of a Ukrainian energy company.
Trump denies there was anything improper about the call or that Zelenskiy was offered a quid pro quo in return for an investigation into the Bidens. Joe Biden is a frontrunner in the Democratic race to elect a candidate to run against Trump in next year’s presidential election.
Since the inquiry began in September, witnesses have testified behind closed doors, so this will be the first opportunity for the public to hear from them directly.
First up are Bill Taylor, acting ambassador to Ukraine, and George Kent, a senior State Department official. Both have testified privately already and were highly critical of Trump's actions in regard to Ukraine.
On Friday, former ambassador to Ukraine Marie Yovanovitch, who was recalled from her post by Trump, will testify. The hearings will begin daily at 10am eastern US time (3pm Irish time) in the ornate room of the ways and means committee of the House of Representatives, but will be led by the House intelligence committee, which comprises 13 Democrats and nine Republicans.
Here are some key points to look out for as the hearings begin.
1) How will House intelligence committee chairman Adam Schiff run the hearings?
Schiff, along with his Republican counterpart Devin Nunes, will control most of the questioning. Each has been allocated a 45-minute slot for questions. However, the rules have been changed to allow for a greater reliance on the committee’s staff during the session, which means that they could drive most of the questioning. This format may avoid the risk of grandstanding by some members of the committee, though each committee member will be allowed five minutes of speaking time.
2) How do Republicans handle the questioning?
Wednesday's testimony should give an insight into Republicans' strategy for defending Trump. All House Republicans voted against an impeachment resolution on October 31st. Since then they have taken several lines of defence, with some arguing there was no proof of a quid pro quo in the July 25th phone call between Trump and Zelenskiy. Others have argued that even if there was a quid pro quo, Trump's sole motive was to root out corruption in Ukraine. There have also been reports that some could seek to pin the blame on Trump associates such as US ambassador to the EU Gordon Sondland, Trump's personal lawyer Rudy Giuliani and acting White House chief of staff Mick Mulvaney.
3) Bill Taylor's testimony
Taylor has arguably given the most damning testimony in private to date. In his 15-page written statement and oral deposition to investigators on October 22nd, he recounted how officials pressured Ukraine to open investigations in exchange for military aid and a meeting for Zelenskiy with Trump in the White House. In particular he described a July 18th conference call when an unnamed Office of Management and Budget official said Trump was freezing $391 million in military aid to Ukraine. Taylor described how he repeatedly complained about the matter to figures including former national security adviser John Bolton, Sondland and secretary of state Mike Pompeo. However, Republicans are likely to argue that he has no direct proof or evidence that the president ordered anything irregular.
4) George Kent's testimony
Kent, the deputy assistant secretary of state for European and Eurasian Affairs at the State Department, delivered testimony in private that was widely seen as supporting Taylor’s account. As the top official in the State Department responsible for Ukraine, he told lawmakers that Trump was demanding that the Ukrainian president open investigations into the 2016 election and into Joe Biden in order to secure an Oval Office meeting. He said he had issued a memo on August 16th outlining his “concerns that there was an effort to initiate politically motivated prosecutions that were injurious to the rule of law, both in Ukraine and the US”. He also alleged that Rudy Giuliani conducted a smear campaign against Yovanovitch, who was removed as ambassador in May.
5) Who else may be ordered to testify?
Wednesday's testimony is the first day of public hearings. To date, Yovanovitch is the only other witness who is scheduled to appear. Some Republicans – including Trump – have suggested that former vice president Joe Biden and his son Hunter should testify, but this is unlikely to be permitted by Schiff. Bolton remains a major figure of interest for the committee. He is waiting to hear the outcome of a court case taken by his former aide Charles Kupperman to establish if he should appear before Congress as requested, or whether he is bound by White House orders not to comply. Mulvaney sought to join the court case over the weekend, suggesting that he too could comply with House subpoenas, but this was refused after lawyers for Kupperman objected.