Express UK|DONALD TRUMP is under intense pressure after Democrats officially launched their case against the White House in the Senate on Thursday – but a shock bombshell on Wednesday could prove to be the catalyst for the President’s downfall and leave him in a scenario as desperate as the one that saw Richard Nixon resign.

President Trump is facing two charges of impeachment – abuse of power, and obstruction of Congress – after he allegedly asked Ukraine’s President to investigate potential 2020 election rival Joe Biden. While the US President has remained defiant in his denials of any wrongdoing, a White House figure has piled on yet more misery for Mr Trump, implying that he knew what was going on as diplomats helped pressure those in Kiev.

Lev Parnas, an indicted associate of Mr Trump’s lawyer – Rudy Giuliani – attended Trump rallies and campaigns during the 2016 election, and became closer to the President’s inner circle following his victory.

Mr Parnas has a Ukrianian background, and therefore claims he was used to help the White House dig up dirt on Democrat 2020 candidate Mr Biden.

But now, the close associate of Mr Trump’s lawyer has told MSNBC in an interview this week that the President was aware of all efforts to investigate his political rival.

Purnas said on Wednesday: “President Trump knew exactly what was going on. He was aware of all of my movements.

“I wouldn’t do anything without the consent of Rudy Giuliani or the president.”

Documents released this week suggest that Mr Parnas was also involved in monitoring the movements of Marie Yovanovitch, who was ambassador to Ukraine until Trump abruptly recalled her last May.

The latest flurry of damning evidence has not prevented Mr Trump from standing firm, as he told reporters that he does not know Mr Purnas “at all, don’t know what he’s about. Don’t know where he comes from. Know nothing about him”.

But, combined with compelling transcripts and a number of witness statements, this latest revelation could prove to be the downfall of the President, mirroring the sudden resignation of Richard Nixon in 1974.

As the Watergate scandal rumbled on and impeachment proceedings were set to escalate to the Senate, the revelation of damining tapes in 1973 confirmed that Mr Nixon tried to block the FBI from investigating the White House break-in.

As scholar Suzanne Garment highlights for Think, once the tape had emerged, Mr Nixon’s support dwindled, even among his Republican allies.

With Mr Purnas dealing another huge blow to the President, Mr Trump’s allies may find it increasingly difficult to stay loyal to their party leader, which could therefore see his charges supported in the crunch Senate vote.

Mrs Garment also highlights that, like Mr Trump, few predicted that the Watergate scandal would oust Mr Nixon from office, and that it only took one huge development to turn the tide.

For now the President holds firm, but with evidence against him growing, his future in the White House could reach a precarious position.