When I was a boy, I liked to listen while my parents and their friends discussed when they had first heard about various significant events: the murder of John Lennon, the assassination of JFK, the Cuban missile crisis. Although the events were grim, there was something comforting about the conversations. Yes, all these terrible things had happened, but here we all were, sitting around, having a cup of tea.

When current affairs turn into history, the edges get rubbed off; they become merely interesting, rather than terrifying. So, thanks are due to Luke Harding for writing Collusion, his book about the ascent to the presidency of Donald Trump, a man so ill-suited to the role that he can’t even hate-tweet the right Theresa May. Once events are confined within a book, they start to feel like the past and less like a constantly perturbing present. I’m not yet ready to reminisce about how Trump trolled the mayor of London during a major terrorist incident, but it’s no longer unimaginable.

Harding is a veteran Guardian journalist, and the author of several books on current affairs (he and I sat next to each other during the public inquiry into the murder of Alexander Litvinenko, and know each other well), often but not exclusively with a Russian focus. There are many angles that a book on Trump could take, but Harding hits squarely at the president’s weakest point: the allegations of cooperation between his campaign and Vladimir Putin’s Kremlin. This, of course, remains a fast-developing story, but it is valuable to be able to sit back and see where it all came from.

For Harding, it began in 2008 when he met Paul Manafort in Ukraine. Manafort went on to become Trump’s campaign manager, and then to be indicted this October for money laundering (he has pleaded not guilty). A decade ago, however, he was working for Viktor Yanukovych, a thuggish Ukrainian crook who had just lost power and was seeking to refashion himself as a modern statesman.

Manafort had worked on multiple US presidential campaigns by then, and had been selling his organisational skills to ex-Soviet insiders since the 1990s, so spinning Yanukovich was just another gig. “He’s still his own man. There is no Russian influence in this campaign. The perception that he is the candidate of Russia against the interests of the west is bad reporting,” Manafort told Harding. It is to Harding’s credit that he lets the irony do the talking there, rather than highlight the parallels immediately clear between the Ukrainian kleptocrat and the man currently in the White House.

And the parallels don’t stop there. Ukraine was a divided country. Ukrainian-speakers, mainly in the capital and the west, looked optimistically towards a future with Europe. Russian-speakers, in the cities and towns of Crimea and the east, where the collapse of communism had doomed a whole way of life, preferred the certainties of their past relationship with Moscow. In 2007, and again in elections in 2010, Manafort and his team rammed a wedge between these groups, playing up their differences, and casting Yanukovich as the candidate for the elderly and the ignored, the opponent of corrupt insiders. It was a winning strategy. “He’s an evil genius,” was one Ukrainian politician’s assessment of Manafort.

If you’ve ever wondered how Trump, a trust fund kid who made a fortune out of gaming the bankruptcy laws, successfully claimed to be the saviour of the left-behind and the scourge of the elite, Ukraine was where his team practised its moves. “Everything he told me was a lie,” Harding notes of his chats with Manafort.

The book’s subtitle is How Russia Helped Trump Win the White House and much of it is structured around the notorious memos written first for a Republican rival of Trump’s and then for the Clinton campaign, which revealed the extent of the Trump campaign’s ties to the Kremlin, as well as other things (prostitutes, wee, etc). Harding has met Christopher Steele, the memos’ author, and provides useful background on him and his career: president of the Cambridge Union, MI6, then his own private intelligence firm.

Steele was so concerned by his findings that he shared them with non-clients, and his memos circulated among Washington journalists in the weeks before the US election. Eventually Buzzfeed published them in full, and ignited the firestorm that has raged ever since. For what it’s worth, I think Russia’s role in this is often exaggerated, perhaps so we don’t have to confront the way wealthy Americans have themselves spent decades perverting their political system. Putin helped Trump win, but only in the way that a 14th pint of beer helps you fall over. It wouldn’t have the same effect if you hadn’t already drunk 13 pints.

But that doesn’t mean the provenance of the 14th pint isn’t important, and Harding’s analysis of Steele’s claims is thorough, fascinating, fast-paced and lively, embedded in a chronological account of the madness we’ve all been living through for the past aeon. Before you read the book, try listing the five worst decisions Trump has made as president; you’ll be amazed by how many you’ve forgotten. When you see them all grouped together, as they are here, you begin to get a sense of the appalled fascination that historians will feel when they come to write about this period.

Part of that fascination will focus on how falsehoods have been transformed into news by the alchemy of social media. Harding tracks one lie – of how British intelligence agencies had bugged Trump on Barack Obama’s behalf – from its birth on Russia’s propaganda channels, to Fox News, to Donald Trump, to his Twitter followers, and into the strange zombie half-life of the “alternative fact”. Every falsehood is another drop of poison in the well we all drink from. The less we trust the news, the more traction Trump’s narcissistic cynicism will gain, and the more his billionaire friends will be free to make money.

So was there collusion between Putin and Trump? Harding lays out what evidence we have, while being clear about the fact we – as yet – don’t know all that much. My own view is that the two presidents are allies of convenience. They and their supporters benefit when their money is left unscrutinised, so both of them oppose any structures that would scrutinise it.

I sincerely hope this book will be the first of many that will do that scrutiny for us. It’s the perfect present for anyone who sees Christmas as a time not just for festivity and merrymaking, but also for fretting about the imminent collapse of the western liberal order.

• Collusion by Luke Harding is published by Guardian Faber (£14.99). To order a copy for £9.99 go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99