Speaker Nancy Pelosi announced that the US House of Representatives would begin a formal impeachment inquiry into Donald Trump, setting the stage for an extraordinary constitutional clash over allegations that the president sought the help of a foreign country to harm a political rival.

“The actions taken to date by the president have seriously violated the constitution,” Pelosi said in a formal address in Washington on Tuesday evening. “The president must be held accountable. No one is above the law.”

Impeachment is a rare and dramatic escalation that will reshape Trump’s already norm-shattering presidency as he seeks re-election. It is also freighted with political risks in a nation deeply divided over this president.

Trump delivered a bellicose response on Twitter, accusing Democrats of “presidential harassment”.

“Such an important day at the United Nations, so much work and so much success, and the Democrats purposely had to ruin and demean it with more breaking news Witch Hunt garbage,” Trump tweeted from New York as he attended the UN general assembly there. “So bad for our Country!”

After months of resistance in the face of calls from many fellow Democrats in Washington, Pelosi appeared to have determined that Trump’s alleged conduct and his administration’s refusal to comply with congressional requests for information and testimony had forced the House’s hand, leaving members no choice but to move forward with a formal impeachment inquiry.

Impeachment: how does it work and what happens next? Read more

During a meeting with the Democratic caucus on Tuesday, Pelosi said that they must “strike while the iron is hot” as she laid out her case for an impeachment inquiry.

“This is a national security issue,” she said, according to a senior aide in the room. “And we cannot let him think that this is a casual thing.”

She vowed to move ahead “expeditiously”.

In her official announcement, Pelosi noted that the chairs of six key House committees already involved in investigating Trump and his administration would make recommendations to the House judiciary committee, which has the authority to handle impeachment. Their reports could help form articles of impeachment brought against the president.

Launching an impeachment inquiry does not necessarily mean that the House will vote to charge the president with “high crimes and misdemeanors”, though that is the likely outcome of such a process. If the House does charge the president, the articles of impeachment would then be sent to the Senate, which is controlled by Republicans who rarely break with Trump.

Pelosi’s announcement follows allegations that Trump pressured the Ukrainian president, Volodymyr Zelenskiy, in a July phone call to investigate the son of Joe Biden, the former vice-president and the frontrunner for the Democratic nomination to compete for the White House in the 2020 presidential election.

Play Video 1:01 'It's a witch-hunt': Donald Trump lashes out as impeachment calls grow – video

Trump has admitted that he discussed Biden on a call with Zelenskiy but has denied any suggestion of a “quid pro quo”, even as it was reported that he ordered his staff to withhold nearly $400m in aid to Ukraine days before his call with Zelenskiy.

The allegations came to light after a whistleblower working in US intelligence filed a formal complaint reportedly related to the phone call. The acting director of national intelligence, Joseph Maguire, refused to release the details of the complaint.

Maguire is due to testify on Thursday, his deadline for turning over the whistleblower complaint to Congress.

“In light of recent reporting on the whistleblower complaint, I want to make clear that I have upheld my responsibility to follow the law every step of the way,” Maguire said in a statement on Tuesday evening. “I look forward to working with the administration and Congress to find a resolution regarding this important matter.”

Trump on Tuesday ordered the unredacted transcript of his summer call with Zelenskiy to be released on Wednesday, the same day the pair are scheduled to meet on the sidelines of the UN general assembly.

“You will see it was a very friendly and totally appropriate call,” Trump tweeted. “No pressure and, unlike Joe Biden and his son, NO quid pro quo!” There’s no evidence to support Trump’s repeated claim that Biden improperly used his position as vice president to fire a Ukrainian prosecutor to help his son.

There is really no other remedy other than impeachment Democratic congresswoman Pramila Jayapal

Later, Trump added: “They [the Ukrainian government] don’t know either what the big deal is. A total Witch Hunt Scam by the Democrats!”



Speaking earlier on Tuesday, Pelosi said Trump did not have to explicitly threaten aid to be guilty of an impeachable offense. “There is no requirement there be a quid pro quo in the conversation,” she said, adding that the “sequence” of events suggested that the president acted improperly.



Later that afternoon, the Senate, in a rare act of bipartisanship, unanimously approved a resolution calling for the DNI to turn over the whistleblower complaint to Congress.

Pelosi’s change of heart came as Democrats from across the party amplified their calls from impeachment after revelations of the whistleblower complaint, which the intelligence community’s internal watchdog, Gen Michael Atkinson, deemed credible and an “urgent concern”. The White House has refused to share the complaint with Congress as typically required by law, arguing that the allegations do not fall within the intelligence community whistleblower statute.

For months, Pelosi had stubbornly resisted calls for Trump’s impeachment, telling colleagues at various points that the president was “not worth” impeaching and that she would rather see him “in prison” than impeached.

The House judiciary committee had been conducting an “impeachment investigation” that centered on the revelations contained in the special counsel Robert Mueller’s report on Russian interference in the 2016 election, as well as several other allegations against Trump, his administration and his financial ties. But now the inquiry has the full support of the speaker, as well as several once reluctant members of Congress.

Facebook Twitter Pinterest The rising sun illuminates the US Capitol Building in Washington. Photograph: Samuel Corum/Getty Images

Republicans said Pelosi’s announcement was a rhetorical exercise.

“She cannot unilaterally decide we’re in an impeachment inquiry,” the House minority leader, Kevin McCarthy, said in brief remarks after Pelosi’s address. “What she said today made no difference with what’s been going on.”

Adam Schiff, the head of the House permanent select committee on intelligence, said on Tuesday that the whistleblower would like to speak to the panel and had requested guidance from the Maguire on how to do so.

The majority of Americans, at this point in time, do not want to see this Democratic congressman Jeff Van Drew

Impeachment is a course of action with few precedents. Only two presidents have ever been impeached – Andrew Johnson in 1868 and Bill Clinton in 1998. Neither were convicted by the Senate. Richard Nixon resigned before a vote on impeachment in the full House could be taken.

In the 24 hours preceding Pelosi’s formal address, dozens of Democrats, including those in districts that voted for Trump, endorsed a plan to move forward with impeachment. Pelosi informed a Democratic caucus meeting on Capitol Hill on Tuesday afternoon of her plans.

“There is really no other remedy other than impeachment,” said the congresswoman Pramila Jayapal, a Washington progressive and an early backer of impeaching the president.

But not all Democrats support impeachment. Congressman Jeff Van Drew of New Jersey said an impeachment inquiry would distract from Democrats’ legislative priorities and deepen the political divides in the country.

“I want to do what’s right. I don’t want to tear the country apart,” he told reporters after the closed-door meeting. “The majority of Americans, at this point in time, do not want to see this.”

