The children’s author Malorie Blackman recently announced she would not accept invitations to US events until the Trump administration’s travel ban on people from seven predominantly Muslim countries is lifted. Members of the UK academic community are also considering whether to boycott conferences in America in solidarity with banned colleagues.

I read about Blackman’s stance while at New York’s LaGuardia airport, waiting for a flight to take me to Missouri, and then on to Ohio and Florida – all states that voted for Trump. For a minute I wondered if I too should down tools, cancel my book tour and fly home to London. Instead I caught my flight to St Louis.

While not opposed to boycotts in principle, I suspect one by authors and academics will have little impact on a president who doesn’t read. A boycott of the companies with links to his businesses is likely to be more effective, as Trump’s angry tweet about Nordstrom dropping his daughter Ivanka’s apparel line illustrates.

I’ve lived in the UK for 30 years, but I am still American. Staying away would be like shunning family. Besides, I am a historical novelist, and want to bear witness.

Everywhere I went in the US I felt something in the air. The most accurate description of this atmosphere is febrile: “characterised by a great deal of nervous excitement or energy”. The Trump administration is busy repealing regulations – on banking, the environment, healthcare – that will have huge impacts. But something about the travel ban has disturbed Americans more than anything else. Maybe it has reminded us that, unless Native American, we are all originally from somewhere else.

Normally apolitical citizens are calling their senators, signing petitions. Institutions are protesting as well. The Museum of Modern Art in New York slyly rehung some of its rooms with art from the banned countries. In Manhattan I stumbled across a demonstration of Google employees and watched as they shouted: “This is what democracy looks like!” Demos often embarrass me, the way clapping along at a concert does. But this one brought a lump to my throat.

Above all, people are talking. Conversations compulsively looped back to the new political landscape. This was to be expected among friends in Boston and New York. Would it feel as feverish in the midwest? Admittedly I was doing events in urban areas that largely supported Hillary Clinton. However, I tried not to assume audiences for my readings would be made up only of liberals. Such assumptions are the kind of sloppy thinking that got us into this mess in the first place. Trump supporters who read books were the people I should be having a dialogue with.

As I began meeting and talking to strangers in Missouri and Ohio, I soon heard impassioned words and opinions, sometimes but not always couched indirectly. An African-American guard at the Toledo Museum of Art in Ohio declared very publicly in the cafe: “This country has done terrible things itself from the very start. Look at it – founded on slavery. How can it dare to criticise other countries?” Yep: febrile in Toledo, too.

Driving through rural Ohio, though, I sensed the political landscape shifting along with the geography. I passed huge churches along the highway, “Choose Life” billboards, a heart-shaped foetus painted on the side of a barn. Abortion was a larger issue in this election than many realised. There were signs advertising hotlines for human trafficking and addiction; from a radio programme I discovered that Ohio has a huge heroin problem. The heartland is … troubled.

In a small-town diner everyone looked up when I came in, I was the only person wearing black and carrying a phone – clearly an East Coast fish out of water. Yet people smiled at me, and went back to their conversations. “Pork bellies stock down,” one baseball-capped man said to another. I guessed I was the only Democrat there but that these were the people I should be reaching out to. But it’s not always easy to start a conversation with strangers who hold a different moral compass. What I wanted to do was hand them one of my books and say: “Read it and tell me what you think.” My novels are not overtly political, but they do explore issues strangely relevant to the US now. At the Edge of the Orchard is about the migration of settlers in the 19th century, a reminder that the US has always been about the unchecked movement of people. A forthcoming novel, New Boy, retells Othello and explores racism in an American school playground.

Back in London, I find that though news about Trump is a constant drumbeat in the media, it feels muffled and less urgent, without the visceral impact it had on me when I had boots on the ground. I want to go back, to do what writers do – listen and record and try to find a common language to throw like a rope across the gulf that divides the country. Because this is what democracy looks like, and feels like, and I am a part of it.

• At the Edge of the Orchard is published in paperback on 23 February