Senior Democratic and Republican US lawmakers presented dueling narratives on Wednesday as a congressional impeachment inquiry that threatens Donald Trump's tumultuous presidency entered a crucial new phase with the first public hearing.
Democrats leading the US House of Representatives probe have summoned three US diplomats - all of whom have previously expressed alarm in closed-door testimony about Trump's dealings with US ally Ukraine - to detail their concerns under the glare of wall-to-wall news coverage this week. The public hearings are scheduled for Wednesday and Friday.
With a potential television audience of tens of millions looking on, Democratic Representative Adam Schiff, chairman of the House of Representatives Intelligence Committee, opened the historic session in an ornate hearing room packed with journalists, lawmakers and members of the public.
"The questions presented by this impeachment inquiry are whether President Trump sought to exploit that ally's vulnerability and invite Ukraine's interference in our elections," Schiff said in his opening statement.
"Our answer to these questions will affect not only the future of this presidency, but the future of the presidency itself, and what kind of conduct or misconduct the American people may come to expect from their commander-in-chief," Schiff said.
Schiff added, "If this is not impeachable conduct, what is?"
This week's hearings, where Americans are hearing directly for the first time from people involved in events that sparked the congressional inquiry, may pave the way for the Democratic-led House to approve articles of impeachment - formal charges - against Trump.
That would lead to a trial in the Senate on whether to convict Trump of those charges and remove him from office. Republicans control the Senate and have shown little support for Trump's removal.
The panel's senior Republican, Devin Nunes, accused the Democrats of conducting a "carefully orchestrated smear campaign" and of using the hearings as a "televised theatrical performance."
He hewed to the Republican strategy of arguing that Trump he did nothing wrong or impeachable when he asked Ukraine's new president to investigate prominent Democrat Joe Biden, a former US vice president and key 2020 re-election rival.
"It's nothing more than an impeachment process in search of a crime," Nunes said.
Schiff said the inquiry looks at whether Trump sought to condition official acts such as a White House meeting or US military assistance on Ukraine's willingness to carry out two political investigations that would help his re-election campaign.
"And if President Trump did either, whether such an abuse of his power is compatible with the office of the presidency?" Schiff asked.
Two witnesses - William Taylor, the top US diplomat in Ukraine, and George Kent, the deputy assistant secretary of state for European and Eurasian affairs - will be the first to testify on Wednesday about whether Trump improperly pressured Ukraine for his own political benefit.
Taylor, a career diplomat and former US Army officer, previously served as US ambassador to Ukraine and is now the chargé d'affaires of the US embassy in Kiev. Kent oversees Ukraine policy at the State Department.
"I do not believe the United States should ask other countries to engage in selective, politically associated investigations or prosecutions against opponents of those in power, because such selective actions undermine the rule of law regardless of the country," Kent said.
The focus of the inquiry is on a July 25 telephone call in which Trump asked Ukrainian President Volodymyr Zelenskiy to open a corruption investigation into Biden and his son Hunter Biden and into a discredited theory that Ukraine, not Russia, meddled in the 2016 US election. Hunter Biden had worked for a Ukrainian energy company called Burisma.
Democrats are looking into whether Trump abused his power by withholding $391 million in security aid to Ukraine - a vulnerable US ally facing Russian aggression - as leverage to pressure Kiev into conducting investigations politically beneficial to Trump. The money - approved by the US Congress to help Ukraine combat Russia-backed separatists in the eastern part of the country - was later provided to Ukraine.
Lawmakers in both parties are playing to a sharply polarized electorate as they move deeper into a six-week-old investigation that has cast a shadow over Trump's presidency with the threat of being removed from office even as he campaigns for a second term.
It has been two decades since Americans last witnessed impeachment proceedings against a president, and these will be the first of the social media era. Republicans, who then controlled the House, brought impeachment charges against Democratic President Bill Clinton in a scandal involving his sexual relationship with a White House intern. The Senate ultimately voted to keep Clinton in office.
Only two US presidents ever have been impeached. No president has been removed through the impeachment process.
Trump has denied any wrongdoing, derided some of the current and former US officials who have appeared before committees as "Never Trumpers" - a term referring to Republican opponents of the president who he has called "human scum" - and branded the investigation a witch hunt aimed at hurting his re-election changes.
Before the start of the hearing, Trump continued to raise doubts about the witnesses' loyalties, tweeting "NEVER TRUMPERS" and reiterating a refrain echoed by his political supporters: "READ THE TRANSCRIPT."
Lawmakers leading the probe released transcripts of closed-door testimony last week showing that Taylor said a White House-led effort to pressure Kiev to investigate Ukrainian energy company Burisma was motivated by a desire to help Trump win re-election next year.
Taylor testified he had been concerned to learn that security aid to Ukraine, as well as a White House meeting between Trump and Zelenskiy, had been delayed for political reasons.
Kent said he had been alarmed by efforts by Trump's personal lawyer, Rudy Giuliani, and others to pressure Ukraine. Kent said Giuliani - who Democrats have accused of conducting a shadow foreign policy effort in Ukraine to benefit the president - had conducted a "campaign full of lies" against Marie Yovanovitch, who was abruptly pulled from her post as US ambassador to Ukraine in May. She will give public testimony on Friday.
Taylor and Kent were testifying together because "they both were witness to the full storyline of the president's misconduct," an official working on the impeachment inquiry said.
Democrats are hoping to convince independent voters and other doubters that Trump was wrong not only in asking Ukraine to dig up dirt on his rival but in making it a "quid pro quo" - a Latin meaning a favor in exchange for a favor.
Republicans want to paint the hearings as a partisan exercise by Trump's opponents who resented failing to gain more politically from former Special Counsel Robert Mueller's investigation that detailed Russian interference in the 2016 election to boost Trump's candidacy. Mueller documented extensive contacts between the Trump campaign and Russia but found insufficient evidence to prove a criminal conspiracy.