Horror, fear, anger, disgust, and shame were just some of the emotions I experienced as I watched Donald Trump's appalling press conference on Wednesday.
If you didn't see it, you cannot begin to imagine how truly terrifying it was. And next Friday, Mr Trump will be sworn in as the 45th president of the United States. It will be recorded in history as one of Western democracy's darkest hours.
As you listen to him take the oath of office -- 'I do solemnly swear that I will faithfully execute the Office of President of the United States, and will to the best of my ability, preserve, protect and defend the constitution of the United States' -- you would do well to remember some of the other things he has said.
'When you're a star, they let you do it. You can do anything ... Grab them by the pussy. You can do anything.' -- September 2005.
'If she [Hillary Clinton] gets to pick her judges, nothing you can do, folks. Although the Second Amendment people — maybe there is, I don’t know.' - 9 August, 2016 (The Second Amendment to the US constitution is the one that enshrines the right 'to keep and bear arms.')
'I'd like to punch him in the face.' - 22 February 2016, referring to a protester at a Trump rally in Las Vegas.
'I don’t like to analyse myself because I might not like what I see.' - Talking to his biographer Michael D'Antonio, in 2014.
Donald Trump is a mean-minded, lying, misogynistic fraud with what appears to be a serious personality disorder. From his stream of public utterances, he seems not to have a generous bone in his body, and to be motivated solely by a combination of hate, greed and extreme narcissism.
His biographer asked him once to name someone whom he respected. 'For the most part,' Trump replied, 'you can’t respect people because most people aren’t worthy of respect.'
It is Trump's misfortune that the man he replaces in the White House brought more grace and dignity to the office of president than any other incumbent in living memory. Barack Obama and his family spent eight years in the glare of the Washington spotlight without even the faintest whiff of scandal or dishonourable behaviour. Donald Trump will move in on day one with a sackload of unsavoury baggage that far outweighs what the Obamas are leaving with.
To put it crudely, whatever you think of his politics or his record, Barack Obama is a far, far better man than Trump will ever be.
So as he takes the oath of office next Friday, remember what his spokeswoman Kellyanne Conway said about him just a few days ago: that we should go by what is in his heart rather than what comes out of his mouth.
It's not easy to know what lies in a man's heart, but nor is it any easier to go by what comes out of this man's mouth.
'I respect the government of Mexico. I respect the people of Mexico. I love the people of Mexico. I have many people from Mexico working for me. They're phenomenal people. The government of Mexico is terrific.' - Press conference, 11 January 2017.
'The Mexican government is forcing their most unwanted people into the United States. They are, in many cases, criminals, drug dealers, rapists, etc.' - Press statement, 6 July 2015.
'I got to know him [Vladimir Putin] very well because we were both on 60 Minutes, we were stablemates, and we did very well that night.' - 10 November 2015.
'I don't know that I'm going to get along with Vladimir Putin. I hope I do. But there's a good chance I won't.' - Press conference, 11 January 2017.
'Russians make up a pretty disproportionate cross-section of a lot of our assets. We see a lot of money pouring in from Russia.' - Trump's son, Donald Jr, at a real estate conference in 2008.
'I have no loans with Russia at all ... I have no deals, I have no loans and I have no dealings.' - Trump at his press conference, 11 January 2017.
Mr Trump also said: 'If Putin likes Donald Trump, guess what, folks? That's called an asset, not a liability.' Perhaps no one has told him that in the world of intelligence-gathering, an asset is someone who provides information, or is in other ways useful, to a foreign power, sometimes because they fear being blackmailed.
We shall see whether Trump or Putin is the bigger liar. It'll be a tough call: remember 'There are no Russian troops in Ukraine'? But if they were rival bullies in a school yard, I know which of them I'd put my money on to emerge victorious from their first head-to-head. And it's not the one who said he doesn't need daily intelligence briefings because 'You know, I’m, like, a smart person.'
As I listened to the president-elect launch his jaw-dropping attack on his own intelligence agencies -- 'I think it was disgraceful ... disgraceful that the intelligence agencies allowed any information that turned out to be so false and fake out. I think it's a disgrace ... that's something that Nazi Germany would have done' -- I imagined Vladimir Putin sitting in the Kremlin, looking like Blofeld, the James Bond villain, stroking a white cat and cackling with delight.
It doesn't really matter whether or not the more lurid allegations are true -- the net effect of their publication is to unbalance, in all senses of the word, an already dangerously unbalanced president-elect. It's bad for the US, and it's bad for the rest of the world. Hardliners from Beijing to Ankara, and from Tehran to Jerusalem, are rubbing their hands with glee as they await the next emotional outburst from the Trump Twitter account. Tensions will rise, sabres will be rattled, and someone, somewhere will do something rash.
Anyone who hopes to see tensions reduced rather than raised will now be looking to members of the US Congress as they contemplate their country's future at the mercy of Donald Trump. And they may recall that what did for Richard Nixon back in the 1970s was a combination of courageous members of Congress, determined reporters, and a legal system that stretched all the way to the Oval Office.
Oh yes, and a deputy director of the FBI by the name of Mark Felt who acted as the Watergate 'Deep Throat', the Washington Post's secret source without whose help President Nixon would never have been brought down.
Mr Trump may well rue the day that he declared war on his own intelligence community.
And now for the good news: starting on Monday, and for four days only, I shall be posting daily extracts from my memoir, Is Anything Happening?, which is being published on Thursday. I hope you'll enjoy reading them and that they will encourage you to buy the book. If you'd like to pre-order a copy, you can do so either at your local bookshop, or online, or direct from the publishers by clicking here.