Trump will rely on McConnell to deliver an acquittal in the Senate if the lower house does go ahead with an impeachment vote
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 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, Taylor recounted in deep detail how Ukraine's new president, Volodymyr Zelensky, came under sustained pressure after taking office.
Taylor said he was told Trump wanted 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."
Another carrot being dangled, Taylor said, was a proposed summit between Zelensky and Trump.
Emerging from the testimony, Democratic congressman Adriano Espaillat tweeted that "what I heard today from #BillTaylor was very troubling and explosive."
"At some point we're going to have to conclude our investigation and go forward with what we have, and what we have is incredibly damning right now," another Democratic legislator, Ted Lieu, said.
Democratic congresswoman Karen Bass told reporters that she thought the Taylor 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 unraveling," she said.
A new CNN/SSRS poll on Tuesday showed support for Trump's removal from office is now 50% to 43% against.
However, reflecting the intensely partisan divide among voters, 87% of Democrats are pro-impeachment, compared to just 6% of Republicans.
Trump admits to asking Ukraine's government to probe what he says is corruption related to 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.
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," 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 Trump.
The White House fought back, with spokesman Hogan Gidley insisting that 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 Trump had made "an unfortunate choice of words."
He added, however, that Trump does have a "legitimate complaint" over a "totally unfair process."
Trump will rely on McConnell to deliver an acquittal in the Senate if the lower house does go ahead with an impeachment vote.