Fifty six years ago, a young Philip Roth despaired at the apparent inability of his chosen trade to compete with the world around him. “The American writer in the middle of the 20th century has his hands full in trying to understand, describe, and then make credible much of American reality,” the novelist declared in his essay Writing American Fiction. “It stupefies, it sickens, it infuriates, and finally it is even a kind of embarrassment to one’s meagre imagination. The actuality is continually outdoing our talents, and the culture tosses up figures almost daily that are the envy of any novelist.”

Roth wrote those words in 1961, when he could look out on the America of John Kennedy, J Edgar Hoover and Malcolm X, not long before the Cuban missile crisis would see the world teeter on the edge of Armageddon. You can see why he felt those engaged in the pretences of fiction had to struggle to keep up when “the actuality” was generating characters of such vivid intensity and events of high drama.

But if that was true then, how much truer is it now? If Roth found himself stupefied, sickened and infuriated in the age of JFK, Bobby and Jackie, what must he make of Donald, Jared and Ivanka? How to top an American president patrolling the late-night corridors of the White House in his bathrobe, casting aside the detailed briefings of the intelligence agencies in preference for the nuggets he can glean from Fox News? A president so consumed with vanity, his staff have learned to drop his name into each paragraph of a memo, lest he grow bored and stop reading? A president who took a wrecking ball to the nation’s health system and then said with a shrug, “Nobody knew healthcare could be so complicated”?

Watch Melissa McCarthy as Sean Spicer on Saturday Night Live

The actuality is continually outstripping even the most outlandish imaginations. Trump can seem more like a cartoon character than a real man. He’s a comic book villain who makes the audience gasp as he fires the straight-backed FBI director James Comey – surely played by James Stewart – or withdraws the US from the Paris accords on climate change, the last best hope for the planet. And the same is true of the minor dramatis personae. Kellyanne Conway, she of “alternative facts”, who went on TV to promote Ivanka merchandise, or Sean Spicer, who seems like a pale imitation of the Sean Spicer played by Melissa McCarthy on Saturday Night Live: these characters don’t resemble real people so much as the creations of an overheated writers’ room. Consider the intelligence leaker whose name was rapidly revealed to be – pause as you take this in – Reality Winner. Few satirists would dare come up with the twists American public life has served up these last few months.

How could any fiction come up with a drama as lurid and compelling as the nightly news from the US?

So how does any novelist, outside those specialising in historical fiction, dare compete? As a writer of political thrillers under the pseudonym Sam Bourne, I confess this question has pressed in particularly sharply in recent months. My new book, To Kill the President, is set in an alternative present day Washington, in which two senior US officials reluctantly conclude that the president poses a danger to the republic and the world – and that it is their patriotic duty to remove him. In the process, I have been exposed to the same challenge posed for the latest season of House of Cards: how could any fiction come up with a drama as lurid and compelling as the nightly news from the US?

This anxiety has a particular edge in the age of Trump, who has defied every norm and crossed every line. The political thriller writer’s objection is not moral so much as practical. Most storylines rely on there being a well-understood set of limits. Writer and reader tacitly agree that there is a category of behaviour that, if revealed, would terminate a politician’s career: overt corruption or sexual abuse, say. This baseline standard can then set a plot in motion: everyone is chasing, for example, a secret tape that, were it ever brought to light, would topple the man in power.

But look at what happened to Trump once the Access Hollywood recording was made public. It had the candidate bragging of sexual assault and grabbing women by the “pussy”, boasting of attempted infidelity while his wife was pregnant with their first child. In most pre-2016 thrillers, that tape would have served as a perfect McGuffin: both the candidate’s allies and enemies would have been desperate to get their hands on it before their opponents did. The action would have been predicated on the wholly reasonable assumption that disclosure would be lethal electorally.

And yet Trump survived, and won. It means the old, assumed boundaries have been erased. Just as journalists, pollsters and political operatives have to rethink their assumptions about the world after 2016, so, too, do thriller writers: they have to work out anew what might count as a fatal blow to the politicians at the hearts of their stories.

This is a challenge, but it’s not an insurmountable one. For one thing, there are still crises and crimes as yet unimagined. No matter what Trump has already done, it’s still possible to dream up atrocious deeds he has not committed – yet. And those can be ascribed to a fictional president in a fictional White House.

Second, even if readers have seen extraordinary things on the news, they have not seen behind the curtain. They have not been taken into those rooms in the West Wing; they have not peeked at the encrypted WhatsApp messages senior White House aides share with each other away from prying eyes. The novelist can at least aim to provide a truth missing from even the most forensic reporting: the texture that lets a reader feel with their fingertips what it’s really like.

Above all, a political thriller can supply a sensation that real life yields too rarely. The narrative should deliver suspense and page-turning excitement, but it can also end in something close to resolution, bringing with it, if we see a bad man brought low, the satisfaction of catharsis. That, I suspect, is one reason why the demand for thrillers has not eased, even in these politically queasy times. They allow us to process the craziness of the real world, to digest it at a metabolic rate and rhythm that suits us. When we hold a book in our hands, we can contain the world: real life is rarely so accommodating.

• To Kill the President is published by HarperCollins. To order a copy for £6.79 (RRP £7.99) go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.