Nancy Pelosi has had a crack at a reporter after announcing she will order articles of impeachment against Donald Trump, saying the US President has left her "no choice but to act".
The House Speaker said investigators have uncovered more than sufficient evidence to show that Trump abused his office for political gain, violating the president's oath to the Constitution and warranting removal.
"Our democracy is what is at stake," Pelosi said.
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She said she was authorising House judiciary chairman Jerry Nadler to proceed with drafting articles of impeachment "sadly but with confidence and humility".
"The president's actions have seriously violated the Constitution," Pelosi said.
Following the announcement, Pelosi held her weekly press conference, where a reporter asked her if she "hated" Trump. The Speaker took umbrage to the suggestion she had anything but "love in [her] heart"."I don't hate anybody," she said.
"And as a Catholic, I resent your using the word 'hate' in a sentence that addresses me."
"I was raised in a way that is a heart full of love, and always pray for the president, and I still pray for the president. I pray for the president all the time. So, don't mess with me when it comes to words like that."
Trump slammed the speaker after she rebuked claims of bias against him, saying she "just had a nervous fit", in a Twitter post. He also suggested she "help the homeless" and said he doesn't believe her earlier assertion that she "prays for the president".
Democrats are now charging toward a pre-Christmas vote on removing the 45th president, a situation Pelosi hoped to avoid but which now seems inevitable. They are considering multiple articles of impeachment against Trump including abuse of power, obstruction of justice and obstruction of Congress.
The House Judiciary Committee will draft one article of impeachment for each alleged offence, and the House will vote on each article separately.
In the House, if a simple majority votes in favour of the articles of impeachment, the chief justice of the Supreme Court will then preside over a trial in the Senate. A two-thirds majority is required to convict and remove a president from office.
Perhaps anticipating Pelosi's statement, Trump goaded the Democrats to move quickly, in a tweet posted moments before the announcement.
"If you are going to impeach me, do it now, fast, so we can have a fair trial in the Senate, and so that our Country can get back to business," he wrote.
"We will have Schiff, the Bidens, Pelosi and many more testify, and will reveal, for the first time, how corrupt our system really is."
In a statement, Trump's campaign manager Brad Parscale said impeaching the President has long been a Democratic goal, "so they should just get on with it so we can have a fair trial in the Senate and expose The Swamp for what it is".
Counsellor to the President Kellyanne Conway also addressed the issue, saying the White House was "very ready" for a Senate trial.
The announcement comes after the first House Judiciary Committee hearing opened on Capitol Hill in Washington on Wednesday to debate the constitutional basis for impeachment and whether Trump's actions meet those standards.
Law professors Noah Feldman, Pamela Karlan and Michael Gerhardt all agreed that Trump committed "the impeachable high crime and misdemeanour of abuse of power" by allegedly attempting to withhold a White House meeting and critical funding from Ukraine as leverage for political favours. He is also accused of soliciting foreign assistance on a phone call with the country's leader.
Harvard professor Noah Feldman testified that Trump has "committed impeachable high crimes and misdemeanours by corruptly abusing the office of the presidency".
Feldman also described how Trump's comments about being able to "do whatever I want as president" under Article 2 of the Constitution had "struck a horror" in him.
University of North Carolina professor Michael Gerhardt told the hearing that Trump had "committed several impeachable offences … worse than the misconduct of any prior president".
"If left unchecked, the President will likely continue his pattern of soliciting foreign interference on his behalf in the next election," he said.
"I just want to stress that if what we're talking about is not impeachable, then nothing is impeachable. This is precisely the misconduct that the framers created a Constitution including impeachment to protect against."
Stanford law professor Pamela Karlan testified that the President's alleged attempt to "strong arm a foreign leader" would not be considered acceptable politics historical standards.
"It is, instead, a cardinal reason why the Constitution contains an impeachment power," she said. "Put simply, a candidate for president should resist foreign interference in our elections, not demand it. If we are to keep faith with the Constitution and our Republic, President Trump must be held to account."
The hearing follows the release of a report on Tuesday detailing the findings of the House Intelligence Committee's investigation last month.
The report alleges the probe into Trump "uncovered a months-long effort by President Trump to use the powers of his office to solicit foreign interference on his behalf in the 2020 election".
The House Intelligence Committee voted to send its landmark report on Trump's conduct to the Judiciary Committee, which will write the articles of impeachment against the President.
At its heart, the 300-page report produced by chairman Adam Schiff's panel lays out the case that Trump misused the power of his office for personal political gain and obstructed Congress by stonewalling the proceedings like no other president in history.
The report does not offer a judgment on whether Trump's actions stemming from a July 25 phone call with Ukraine rise to the level of "high crimes and misdemeanours" warranting impeachment. The entire House will decide that question as soon as this month.
The Republicans' sole witness to testify Wednesday, Jonathan Turley, a professor at the George Washington University Law School, said "we're all mad" — but that doesn't mean impeachment is the answer.
"I get it. You're mad. The President's mad. My Republican friends are mad. My Democratic friends are mad. My wife is mad. My kids are mad. Even my dog seems mad — and Luna is a golden doodle and they don't get mad," he said.
"So we're are all mad, and where has it taken us? Will a slipshod impeachment make us less mad? Will it only give an invitation for the madness to follow in every future administration?" he added. "This is not how you impeach an American president.
"President Trump will not be our last president and what we leave in the wake of this scandal will shape our democracy for generations to come.
"I am concerned about lowering impeachment standards to fit a paucity of evidence and abundance of anger."
Trump slammed the case for his impeachment as a "joke" and lambasted his opponents for proceeding with hearings during his trip to a NATO summit in Britain.
"What they are doing is a very bad thing for our country," he said when asked about the report from the House Intelligence Committee. "It's a joke."
Trump said it was a "disgrace" that the House Judiciary Committee was holding a hearing Wednesday to consider drawing up articles of impeachment "when we are in London".
House Judiciary Committee ranking member Doug Collins criticised Wednesday's hearing during his opening statement by noting that it did not include any fact witnesses, only law professors who he claimed would likely just theorise about impeaching Trump because they were too busy to digest all of the facts at hand.
One of the witnesses, Stanford Law Professor Pamela Karlan, took umbrage with Collins' statement, stating that she is quite familiar with the facts of the case, and would not be there otherwise.
"Here Mr Collins, I would like to say to you, sir, that I read transcripts of every one of the witnesses who appeared in the live hearing, because I would not speak about these things without reviewing the facts," she said during her opening remarks.
"So I'm insulted by the suggestion that as a law professor I don't care about those facts."
Democrats claim Trump held back nearly US$400 million in military aid from the Ukraine as part of an alleged bribe for political gain. The President is also accused of soliciting foreign interference in the 2016 US election.
The inquiry focuses on a July 25 phone call in which Trump asked Ukraine's new president Volodymyr Zelensky to carry out two investigations that would benefit him politically, including one targeting Democratic political rival Joe Biden.
During the call, the President asked Zelensky to do him a "favour" and investigate the origins of the Russia probe, which by July had already ended, and to investigate Mr Biden and his son Hunter, who served on the board of a Ukrainian natural gas company.
The requests came immediately after the Ukrainian President thanked Trump for America's defence support and said his country was "almost ready" to buy more US military technology. Trump has repeatedly denied any wrongdoing and described the inquiry as a "witch hunt".
Republicans on the Intelligence Committee released their own report, exonerating Trump for his actions with Ukraine by saying the military aid was never used as leverage and was eventually released on September 11.
Trump's impeachment by the Democratic-controlled House would place the President on trial in the Senate, where a Republican majority could protect him from removal.