Jill Lepore is professor of American history at Harvard and a prolific essayist for the New Yorker. Her books have included These Truths, a 900-page chronicle of American democracy and The Secret History of Wonder Woman. Her new book, If Then, tells the story of the Simulmatics Corporation – “the Cambridge Analytica of the 1960s” – which used emerging computer technology to try to predict human behaviour and win elections. This interview took place the day before the first US presidential debate.

Reading about the extraordinary history of the Simulmatics Corporation and its “People Machine”, it was instructive to see how the anxieties we have today about the more sinister aspects of computer technology were very present 60 years ago. Did that surprise you?
If anything, I think in the 50s and 60s – because so few people had direct experience of computers – there was even more concern than there is now. Computers were associated with vast power. It was only with the arrival in the 1980s and 1990s of the personal computer we were sold the idea that the technology was participatory and liberal. I think we have returned, in a way, to the original fears, now we sense that these personal devices very much represent the power of vast corporations.

The Simulmatics story is also an early example of using big data as a con trick, making claims it could not back up. You obviously saw a parable in that as well?
The product they were selling was the accurate prediction of human behaviour. There was inevitably a lot of hucksterism attached to it and that hasn’t changed.

Do you think we should in general pay more attention to those origin stories of computer technology, that all the issues we are facing today were wired in from the start?
One of the myths of Silicon Valley is that everything is always brand new. The fact is that most of those new ideas are not only deeply derivative, but specifically derivative of the national security objectives of the United States during the cold war. Our culture of technological utopianism wants to forget that.

In terms of the effect of social media on democracy, alarm bells have been ringing loudly since 2016. How can we still be going into elections without any reform?
After the second world war, the new technologies that had contributed to the atom bomb or the science that had been misused by the Nazis were a source of huge moral concern and new international rules were put in place to control those forces. The field of bioethics emerged out of the Nuremberg trials. In terms of social media, and computer science more generally, that Nuremberg moment should have been 2015 and 2016. Trump was elected with legitimate votes, but from what we have discovered about the spread of misinformation it was clear that we cannot have a properly functioning democracy without some regulation of that media. The difference is that the technological advances of the war were made primarily by academics, whereas the people who are developing these tools are cashing them out for billions of dollars.

When the Cambridge Analytica story came out, or clear evidence was revealed about the way social media platforms had been targeted at scale by foreign agents, there was remarkably little outcry. Why do you think that was?
I think the fallout of social media and data mining is invisible to most people. The bamboozling is part of it. When Mark Zuckerberg appeared before Congress and said: “We are in the business of connecting people to people they love”, no one called him out to say: “No, Mr Zuckerberg you are in the business of convincing people to give you their personal data and selling it to third parties. You are selling loneliness and outrage and are profiting from the destruction of our system of representative government.”

The final chapter of These Truths, your history of the United States, was supposed to be the inauguration of Obama, a symbolic climax of a long arc of history. But in fact you were forced to end it with the election of Trump. How much of an outlier did that event look to you?
Historians are always asked if events are unprecedented and for most of my career I have resisted that idea. There was a point when Trump was elected when I was thinking, well he’s clearly a fraud and a monster but there were nevertheless some rational reasons why people voted for him. But it became clear that this was actually without precedent – he crossed so many lines.

Does the effect of new technology begin to explain that historical anomaly?
Yes and it also makes it very hard to fix anything. American political history begins with the technology of writing – Christopher Columbus keeps a log book – and with printing. And then it was changed by radio and television and so on. Things are briefly upended by new technologies before finding a new equilibrium. With social media, that equilibrium has not happened. The question is how do you repair the fabric of democracy when the technology is itself built to polarise us? It is like we have built a perfect trap for ourselves. That is what leaves me so frankly terrified.

How are you viewing November? With trepidation?
Of course. The New York Times yesterday asked the question: “If on election night, Trump tweets that he has won, before the mailed-in ballots are counted – what would be the response of Google and Twitter and Facebook?” It’s a fair question – one would hope they have a plan – but how did we get into this situation where it is up to those companies to have the plan? When did we hand them the reins?

Where do you place your hope for refashioning democracy in the future?
I sometimes wonder if the profound atomisation and isolation of the pandemic might have brought home to people how essential human connection, physical connection, is for us all. Filling up a kitchen with the sound of conversation. If people with a platform could speak to this and find a way to articulate how that we can’t live in isolation, throwing our garbage over the wall and distrusting our neighbours, then there is a different possibility. That’s probably daffy, but that’s my hope.

What books do you have by your bedside?
A few, but generally a PD James.

• If Then: How the Simulmatics Corporation Invented the Future by Jill Lepore is published by John Murray Press (£20). To order a copy go to guardianbookshop.com. Free UK p&p over £15