Democratic impeachment prosecutors have begun formal arguments in the Senate trial, presenting a meticulous and scathing case for convicting Donald Trump and removing him from office on charges of abuse of power and obstruction of congress.

Representative Adam Schiff, chair of the House Intelligence Committee, took the lectern in the chamber as senators sat silently preparing to weigh Mr Trump’s fate. Speaking in an even, measured manner, Mr Schiff accused the president of a corrupt scheme to pressure Ukraine for help “to cheat” in November's presidential election.

Invoking America's founders and their fears that a self-interested leader might subvert democracy for his own personal gain, Mr Schiff argued that the president’s conduct was precisely what the framers of the constitution had in mind when they devised the remedy of impeachment, one he said was “as powerful as the evil it was meant to combat”.

“If not remedied by his conviction in the Senate, and removal from office, President Trump’s abuse of his office and obstruction of congress will permanently alter the balance of power among the branches of government,” Mr Schiff said in his opening remarks. “The president has shown that he believes that he’s above the law and scornful of constraint.”

The Senate proceeding, the third impeachment trial of a president in US history, was fraught with partisan rancour and political consequence both for Mr Trump and for the two parties grappling over his future.

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In a series of speeches, Mr Schiff and the six other impeachment managers asserted that the president pressured Ukraine to announce an investigation of former vice president Joe Biden and his son, Hunter Biden, while withholding as leverage nearly $400m (£304m) in security aid for Kiev and a White House meeting for its president. When he was caught, they said, Mr Trump ordered a cover-up, blocking witnesses and denying congress the evidence that could corroborate his scheme.

“President Trump withheld hundreds of millions of dollars in military aid to a strategic partner at war with Russia to secure foreign help with his reelection,” Mr Schiff declared. “In other words, to cheat.”

The Democrats will continue to lay out their now-familiar case on Thursday, although there is little doubt about the outcome of the trial. It is all but certain to end in Mr Trump’s acquittal in the Senate, where it would take 67 votes to convict and remove him. But the contours of the trial remained up in the air, as Republicans and Democrats continued to feud over whether to consider additional evidence, including witnesses Mr Trump has forbidden from cooperating with the inquiry.

Mr Trump — impatient for his legal team to have a chance to mount a vigorous defence of his behaviour — was on the other side of the Atlantic, hurling insults at the impeachment managers and telling reporters he would like to personally attend the Senate trial in order to “sit right in the front row and stare into their corrupt faces.”

At a news conference in Davos, Switzerland, where he was attending the World Economic Forum, Mr Trump said that John Bolton, the former White House national security adviser, could not be allowed to testify because he “knows my thoughts on certain people and other governments, war and peace and different things — that’s a national security problem.”

Mr Schiff insisted in his opening arguments that fairness demanded hearing from Mr Bolton, who has pledged to testify if the Senate subpoenas him, and other White House officials. Democrats angrily rejected the suggestion that they might agree to call Hunter Biden in exchange for Mr Bolton’s appearance.

“This isn’t like some fantasy football trade,” Mr Schiff said before the trial commenced on Wednesday. “Trials aren’t trades for witnesses.”

Senator Chuck Schumer, the Democratic leader, told reporters the idea was “off the table.”

Campaigning in Iowa, Joe Biden was adamant in rejecting any testimony trade-off. “This is a constitutional issue,” he said. “We’re not going to turn it into a farce, into some kind of political theatre.”

A set of closed-door negotiations among senators appears likely to soon intensify as Democrats plot their strategy for winning a vote on witnesses, which would require the votes of a handful of centrist Republican senators who have signalled they are open to the idea. Votes on the matter are likely to come next week, after the House managers and White House lawyers complete their arguments, and senators have had a chance to submit questions about the case.

For now, the president’s legal team must sit silently in the chamber as the president’s House accusers have exclusive access to the microphone. Under the rules of the trial adopted on Tuesday, the House managers have 24 hours over three days to present their case, leaving White House lawyers to take in their searingly argued case about Mr Trump’s actions, with no opportunity for immediate rebuttal.

The president vented rabidly about the process on Twitter, firing off so many posts that he set a record for any single day in his presidency.

As of 11:30pm EDT, Mr Trump had posted or reposted 142 tweets, surpassing the previous record of 123 set in December. Most were retweets of messages from allies and supporters assailing Mr Schiff and others prosecuting the case.

During a dinner break on Wednesday, Jay Sekulow, the president’s personal lawyer, raced to face reporters, vowing to eventually respond “to what the House managers have put forward, and we are going to make an affirmative case defending the president.”

The tables will turn this week, most likely on Saturday, when the defence will be given its own 24 hours of uninterrupted time to play to the cameras from the Senate floor, with House Democrats sidelined. The defence of the president could continue into early next week after a break on Sunday.