LAHORE: Mohsin Hamid is depressed. The novelist, twice nominated for the Man Booker prize, has seen the three places he calls home – Pakistan, America and Europe – betray their fundamental ideals and become increasingly unwelcoming.

In Pakistan, where he was born, the elected government caved in to a mob of extremist protesters by sacking a minister they accused, essentially, of being a bad Muslim. In a country created as a homeland for south Asia’s Muslims, the fight over who fits that bill means hardly anyone is safe from unfounded accusations of blasphemy. Students have been lynched arbitrarily and, in 2011, the governor, Salman Taseer, was shot for criticising the blasphemy laws. To Hamid, the stunning capitulation to the mob signals the breakdown of an uneasy coexistence between the government, the military and the courts, allowing “raw power” to rule.

“These are incredibly disheartening times. I feel more depressed than I have in a long time about the political direction of Pakistan,” Hamid tells The Guardian. “Since Pakistan was founded in 1947, there has been a conflict between the notion that citizens are equal, and that certain people can ascribe to themselves the right to decide who is Muslim,” he says. “The question is: who is Muslim enough? And 70 years after creation, the answer is that nobody is Muslim enough.”

But Pakistan is not alone in narrowing definitions of who belongs. Hamid thinks western countries that tout principles of equality fail one group in particular: migrants.

That is the topic of his recent novel Exit West, a story of desperation, love and, ultimately, liberation, which won him a second Man Booker shortlisting this year following that for The Reluctant Fundamentalist in 2007.

The plot of Exit West revolves around Saeed and Nadia who secretly fall in love in a nameless city under siege. When they flee to Europe, they are met with militarised borders and unfriendly natives whose hostility reminds Nadia of “the fury of the militants in her own city”. Migration is driven by touches of magical realism. People travel through mystical doors, emerging in an instant in faraway places.

Hamid, 46, has himself divided his life between Pakistan, Britain, where he also holds citizenship, and the US. He is a product of western democratic traditions but also of life in a developing nation among countrymen who are desperate to leave but cannot.

“That infection combined with an American constitutional system and European social democracy results in weird thoughts like, ‘what if people could also move freely?’” he says, explaining the idea of the doors. “As a mongrelised human being, I don’t find the world around us satisfactory.”

Hamid skips the traumatic migrant journey and goes straight to the collision of cultures, which in the novel gives way to a new and richer world once the migrants settle.

In reality, of course, most migrants are kept at bay in camps, in what Hamid sees as an attempt to “impose a condition that humanity has never known before, which is an end to migration”. The only way to achieve that goal, he says, is to militarise borders and “mete out on the migrants a level of horror that counterbalances the horror facing them where they’re from so they don’t come any more”.

Pakistan is a model for the kind of things that occur when the idea of purity is made predominant in your society

That, in turn, reveals the limits of the “western humanist notion”, Hamid says. “We say we believe that if you’re black or white, you’re equal, or if you’re male or female, you’re equal, if you’re gay or straight, you’re equal,” he explains. “But one of the subversive questions that fiction can ask, and that this book in particular tries to ask, is why are the child born in Mogadishu, and the one born in Milan or Minneapolis, not equal?”

“The entire system of the nation state, global governance, democracy has this huge lacuna at the heart of it,” he says.

At some point, humanity will see a movement for migrants’ rights, similar to the ones for women, African Americans and gay people, he says. The alternative will wreak “such monstrous havoc” both on migrants and those denying them their rights, that it becomes unsustainable.

The political consequence of undermining human dignity and equality is that people in the west will stop believing in these principles and turn to tribalism, he says.

However, tribalism is at odds with modern nation states and can lead to separatism, as seen in Catalonia and post-Brexit Britain, which Hamid describes in the novel as “a man whose head had been chopped off and yet still stood”.

Tribalism will drive the west in the direction of Pakistan, he says – a fundamentally diverse society growing increasingly fragmented between various communities who all define themselves based on ideas of a pure identity.

“You’ll see Pakistan, basically, all over Europe and North America,” he says with a laugh. “We are the cutting edge. Pakistan can be viewed as a model for the kind of things that begin to occur when [the idea of] purity is made predominant in your society.”

In Exit West, large-scale migration leads to conflict, but it is not a dystopian tale. Beyond the initial shock and clash of peoples emerges humanity in all its diversity. Ultimately, for Hamid, migration is a force of hope.

“The hope is that new cities are born, people move, new stuff begins to happen, better food is created, there’s better music, people having sex who wouldn’t be having sex before, and enjoying it much more now,” he says.

“If Copenhagen is like Rio de Janeiro in 100 years, maybe people of Copenhagen today will think that’s a disaster, but maybe their grandchildren will think it’s fantastic.”