The top US diplomat in Ukraine poured fuel on Donald Trump's impeachment probe on Tuesday with a detailed account of how the president pushed Kiev to discredit one of his main political rivals, withholding US military aid to exert pressure.
Democrats said the congressional testimony by Bill Taylor was a stunning confirmation of their allegations that Mr Trump abused his office by seeking foreign help to hurt Democratic candidate Joe Biden in the 2020 presidential election.
"It's all there. What's there left for me to say when you have such a clear and detailed statement?" said House Democrat Tom Malinowski, a former diplomat.
The White House rejected what it called a "coordinated smear campaign from far-left lawmakers and radical unelected bureaucrats."
"Today was just more triple hearsay and selective leaks from the Democrats' politically-motivated, closed-door, secretive hearings," the administration said in a statement.
"Every day this nonsense continues more taxpayer time and money is wasted."
In a 15-page opening statement quickly leaked to US media, Mr Taylor recounted in deep detail how Ukraine's new president, Volodymyr Zelensky, came under sustained pressure after taking office.
Mr Taylor said he was told Mr Trump wanted Mr Zelensky "to state publicly" that he would investigate Biden and his son Hunter for what he said was corruption in the ex-Soviet republic.
He said that the US ambassador to the European Union, Gordon Sondland, told him that "'everything' was dependent on such an announcement, including security assistance."
Democratic congresswoman Karen Bass told reporters that she thought Mr Taylor's testimony "was shocking."
"We still need to go through the process. It's kind of like a string of a sweater in the sense that it's just unravelling," she said.
A new CNN/SSRS poll on Tuesday showed support for Mr Trump's removal from office is now 50 per cent to 43 against.
However, reflecting the intensely partisan divide among voters, 87 per cent of Democrats are pro-impeachment, compared to just six per cent of Republicans.
US President Donald Trump. Source: AFP
Racism storm
Mr Trump admits to asking Ukraine's government to probe what he says is corruption related to Mr Biden.
However, he denies Democrats' allegation that he tried to strong-arm the Ukrainians by linking the delivery of US military aid to his request for an investigation.
Mr Trump has already branded the impeachment proceedings a "coup," a "hoax," a "witch hunt" and a variety of swear words.
On Tuesday, he prompted an uproar by claiming he was the victim of a lynching, a word linked in the United States to the darkest days of slavery's aftermath.
"All Republicans must remember what they are witnessing here - a lynching," Mr Trump tweeted.
More than 3,400 African Americans were lynched between 1882 and 1968, and congressional Democrats reacted with collective anger.
"How dare you?!" seethed congresswoman Barbara Lee on Twitter as she assailed the "disgusting and ignorant message" from Mr Trump.
The White House fought back, with spokesman Hogan Gidley insisting that Mr Trump did not mean to compare "what's happened to him to one of the country's darkest moments."
There was rare criticism from the top Republican legislator, Senator Mitch McConnell, who said Mr Trump had made "an unfortunate choice of words."
He added, however, that Mr Trump does have a "legitimate complaint" over a "totally unfair process."
Mr Trump will rely on Mr McConnell to deliver an acquittal in the Senate if the lower house does go ahead with an impeachment vote.
'Crazy'
Mr Trump did urge Mr Zelensky in July to investigate Joe Biden and his son, according to a summary of a phone call released by the White House.
Seeking help from a foreign country in a domestic election is illegal in itself, but a whistleblower complaint about the call made the more serious allegation that Mr Trump also sought to condition nearly $400 million in military aid to Ukraine on Kiev launching a probe.
Mr Taylor is a military veteran and career diplomat who served as US ambassador to Ukraine from 2006 to 2009, and is now charge d'affaires following the ouster of ambassador Marie Yovanovitch this year.
Ms Yovanovitch testified to Congress two weeks ago, telling House investigators she was pushed out on "false claims" that she had disparaged Mr Trump.
According to Mr Taylor, much of the pressure he described was applied through "weird" back channels, including Mr Trump's personal lawyer Rudy Giuliani.
Mr Taylor had already damaged Mr Trump's defence with a paper trail that included text messages in which he expresses alarm about having to pressure Mr Zelensky's government.
"Are we now saying that security assistance and WH (White House) meeting are conditioned on investigations?" Mr Taylor asked Sondland in a September text message.
Later, Mr Taylor expressed more explicit reservations to Sondland: "I think it's crazy to withhold security assistance for help with a political campaign."
On Tuesday, Mr Taylor said in his opening statement that he stood by that characterisation of the quid pro quo being "crazy."
