My favourite film of all-time is “All the Presidents Men”. The 1976 political thriller based on the true story of the Watergate scandal stars Robert Redford and Dustin Woodward as the journalists Carl Bernstein and Bob Woodward of the Washington Post. SPOILER ALERT: Their reporting contributed to the resignation of US President Richard Nixon. As with many political scandals it was the attempted cover up that finally caused Nixon to resign ahead of his likely impeachment.

I’ve been recalling the excellent film in recent days as news emerges about the growing scandal engulfing current US President Donald Trump. Yesterday’s Washington Post printed the full whistleblower complaint which is at the heart of the allegations: that the US president applied pressure on Ukraine to target his leading Democratic presidential rival Joe Biden. Widely believed to be by a CIA officer, the complainant accuses Mr Trump of “using the power of his office to solicit interference from a foreign country in the US 2020 election”. The conduct of the president is described as a “serious or flagrant problem, abuse, or violation of law”.

What is beyond dispute is that Donald Trump had a telephone call with Ukrainian president Volodymyr Zelensky, discussed Mr Biden’s son, Hunter Biden, and unsubstantiated allegations that the then US vice-president – stopped the prosecution of his son by lobbying Ukraine to fire a prosecutor. During the call, Mr Trump asked Mr Zelensky to work with US Attorney General William Barr and Mr Trump’s personal lawyer, Rudolph Giuliani, to look into the matter. All of this happened just after Trump paused the payment of millions of dollars of aid to Ukraine. So far, so complicated.

What is a lot simpler to understand is the allegation that senior White House officials apparently attempted to “lock down” all records of the call, especially the official word-for-word transcript. “This set of actions underscored to me that White House officials understood the gravity of what had transpired in the call,” the whistleblower wrote in his or her complaint. The allegations state that the call details were stored in a “stand-alone computer system reserved for codeword-level intelligence information, such as covert action”. What will particularly interest a forthcoming inquiry is the detail from the whistleblower that officials said it was “’not the first time’ under this administration that a presidential transcript was placed into this codeword-level system solely for the purpose of protecting politically sensitive – rather than national security sensitive – information”.

Oh! Well at that point my ears really pricked up. What already seemed pretty spicy, became even more interesting. Remembering back to what happened in the Watergate investigations, Nixon survived the drip-drip-drip of details and allegations until the record of cover-up was released: in the form of the so-called “smoking-gun” tape. At that point all the bluster and denial was for the birds.

President Trump of course vehemently denies doing anything wrong, that it is all a Democrat ‘witch-hunt’ and a ‘hoax’. He’s gone on the offensive demanding to know who provided information to the whistleblower – and describes them as “close to a spy”.

In what can only really interpreted as reference to the execution of spies by the US in the past, he added with a nod and a wink: “You know what we used to do in the old days when we were smart? Right?”

Nearly half a century after Watergate and 20 years after the Clinton scandal we are right back in an impeachment drama that will dominate debate in the United States, in what is the run-up to the next presidential election. According to the House Intelligence Chairman Adam Schiff: “The President of the United States has betrayed his oath of office, betrayed his oath to defend our national security, and betrayed his oath to defend our constitution.”

The key questions that investigations will try to get to the bottom of are: Did President Trump abuse the power of his office by using hundreds of millions of dollars in US taxpayer aid to pressure a foreign country to damage a presidential rival? And, did the White House then cover it up?

Just like the Boris Johnson is currently doing with his "People vs ParliamentBrexit campaign, Trump and his supporters are pursuing a “scorched earth defence”, claiming that impeachment is all about subverting the elected president of the United States.

But as facts continue to emerge, it is going to be the facts that matter, or at least they should. As Robert Burns wrote: “Facts are chiels that winna ding”, in English translation “But facts are fellows that will not be overturned”. Let us hope that this is true. I for one will look forward to seeing “All the Presidents Men II”.