Donald Trump has raged about the alleged unfairness of the impeachment process confronting him, as his lawyers have urged the Senate to swiftly reject the charges.

Less than a day before the upper chamber of congress convenes for only the third time in history to consider impeachment charges against a president, Mr Trump blasted Democrats for having overseen a process he said was skewed against him.

“Cryin’ Chuck Schumer is now asking for ‘fairness’, when he and the Democrat house members worked together to make sure I got ZERO fairness in the house, he tweeted. “So, what else is new?”

The president’s comments on Twitter came as his lawyers urged senators to reject the two articles of impeachment that were approved by the House of Representatives, and sent up for trial – one of abuse of power, and one of obstruction of justice. ​In a 110-page document filed before a noon deadline, his lawyers claimed the president had done nothing wrong, that the case against him involved a twisting of the constitution, and that it was part of a broader “illegitimate partisan effort to take him down” by Democrats.

Later, the Republican leader in the Senate Mitch McConnell, proposed a condensed, two-day calendar for each side to give opening arguments. It also pushed off any votes on witnesses until later in the process, rather than up front, as Democrats demanded.

All the president's lawyers: The team fighting Trump's impeachment Show all 6 1 /6 All the president's lawyers: The team fighting Trump's impeachment All the president's lawyers: The team fighting Trump's impeachment Alan Dershowitz Dershowitz is a controversial American lawyer best known for the high-profile clients he has successfully defended. Those clients have included OJ Simpson, Jeffrey Epstein and Harvey Weinstein. One longtime Harvard Law associated told the New Yorker Dershowitz "revels in taking positions that ultimately are not just controversial but pretty close to indefensible." Getty All the president's lawyers: The team fighting Trump's impeachment Ken Starr Starr became a household name in the 1990s as the independent counsel who led the investigation that led to Bill Clinton's impeachment. That investigation began as a look into a real estate scandal known as Whitewater, and eventually led to impeachment after Mr Clinton lied under oath about having an affair with White House intern Monica Lewinsky. AP All the president's lawyers: The team fighting Trump's impeachment Jay Sekulow Sekulow is the president's longtime personal attorney, and, now, personal lawyer in the White House. He has been accused by former Rudy Giuliani associate Lev Parnas of being "in the loop" during the Ukraine scandal. Getty All the president's lawyers: The team fighting Trump's impeachment Pam Bondi Bondi is the former attorney general in Florida, and a longtime backer of the president's. She made a name for herself in Florida for taking hyper partisan stances on issues, and her penchant for publicity. She is likely to be a prominent public-facing figure during the trial. AFP/Getty All the president's lawyers: The team fighting Trump's impeachment Pat Cipollone Cipollone is the White House counsel, and leading the president's defence team. Getty All the president's lawyers: The team fighting Trump's impeachment Rudy Giuliani While not officially named as one of the president's impeachment lawyers, it is hard to ignore Giuliani's outsized role in this process. The former mayor of New York has been making headlines for months as he defends his client, and for his apparent role in the effort to compel Ukraine to launch the investigation into Joe Biden. We'll see how he figures in the actual trial, which he has said he would like to be a part of. Reuters

The case against Mr Trump was triggered after revelations emerged last autumn from a member of the US intelligence community that the president had on a 25 July phone call with the leader of Ukraine, improperly asked him to launch an anti-corruption probe into Democrat Joe Biden and his son, Hunter.

The former vice president is among a handful of Democrats vying to take on Mr Trump later this year.

It was alleged that in exchange for Kiev’s launching of such a probe, the White House would invite the newly elected Volodymyr Zelensky to Washington DC, and lift the freeze on around $400m in military aid that had been assigned by congress to help Ukraine bolster its defences against Russia, amid long-running hostilities.

Donald Trump may discuss hacking of firm at heart of Ukraine scandal with Putin, Kellyanne Conway says

After the House voted almost strictly on party lines to approve the two articles – the lower chamber voted 230-197 on abuse of power, and 229-198 on obstruction of congress – the drama was expected to move swiftly to the Senate, where Republicans hold a majority and the president would expect to be acquitted.

But in a sharp display of political manoeuvring, house speaker Nancy Pelosi delayed sending the articles to the Senate, claiming Republican leader Mitch McConnell had made clear he would not permit a fair trial, and dismissed efforts by Democrats to call witnesses.

Even at this stage, many of the details of how the process will play out remain unclear, and late on Monday, Democrats assigned by Ms Pelosi to oversee the prosecution of the case against Mr Trump, were still in discussions with Republicans in the Senate.

Before senators from either side make any progress in making the case against the president or seeking to dismiss it, the Senate will have to vote on a resolution to govern the hearings. Late on Monday, Mr McConnell proposed a condensed, two-day calendar for each side to give opening arguments, and sought to claim witnesses would only be permitted if there was a separate vote. Democrats termed his proposal a “cover-up”.

Republicans control the chamber 53 – 47, so Mr McConnell can expect considerable leverage in setting the terms. In recent days, he and other party lawyers from both sides have been studying the way the Senate handled the 1999 case against Bill Clinton.

On that occasion, when Democrats controlled the chamber, a total of three witnesses, including former White House intern Monica Lewinsky, gave video depositions, excerpts of which were played. No live witness testimony was permitted in the chamber.

The Senate could vote for witnesses with just a simple majority. As a result, Democrats could need to persuade just four Republican senators – they are targeting the likes of Susan Collins and Lisa Murkowski – to hear from them.

On Monday, The New York Times pointed out Mr Trump’s legal team did not deny he pressured Ukraine to announce investigations into Mr Biden. Yet they claimed he had the authority to conduct relations with other countries as he wished.

After Mr Trump’s lawyers filed their legal brief, Democrats in the House responded.