This is a mammoth subject and not just because Donald Trump based much of his success in the US electoral college (if not the US popular vote) by claiming at every opportunity that he would “build that wall”.
So Marshall explores how different societies have responded to the changes wrought by our globalised world and how they rise to the challenge of maintaining national identity.
Trump’s America, he argues, is “the only major power that can absorb the potential losses of withdrawing from globalisation without seriously endangering itself in the short term”.
But Trump’s border wall is a rhetorical device that plays on a fear of other peoples. It is unlikely ever to be built, not least because about two-thirds of southern borderland property and land is in private ownership, but it reassures his core voters.
Next Marshall turns his attentions to China, home of the Great Wall, where the state has responded to global upheaval by restricting its citizens’ access to the internet.
This is his cue to explore cyber security and “the Great Firewall of China”. As Marshall argues, “internet censorship does restrict China’s economic potential” but that is a price that the Chinese Communist Party is willing to pay to maintain both its power and national unity.
Subsequent chapters examine Israel and Palestine where walls are a necessity but they are “containing the violence – for now”.
In the wider Middle East, Marshall argues that “ironically, another wall is needed… between religion and politics” if the region is to escape its troubled past.
The Indian subcontinent contains the longest border fence in the world which runs for 2,500 miles between India and Bangladesh.
But the area is still struggling to cope with mass migration as well as climate change.
Seven out of 10 of the world’s most unequal countries are to be found in Africa. Marshall focuses on the legacy of colonialism and influences of globalisation which, he argues, “has lifted hundreds of millions of people out of poverty” while widening the gap “between the rich and not rich”.
The final two chapters focus on Europe and the UK with Marshall exploring “the new realities of mass immigration and the moral necessities to take in refugees”.
He shows how population pressures have led to the rise of nationalism and the Far-Right. Nonetheless he argues that we still need our nation states because “communities need to be bound together in shared experience”.
Walls, Marshall concedes, have their place and we need not necessarily “decry the trend of wall-building… they can also provide temporary and partial alleviation of problems, even as countries work towards more lasting solutions, especially in areas of conflict”.
The book closes with suggested solutions to the world’s problems, including “a 21st-century Marshall Plan for the developing world to harness the riches of the G20 group of nations in a global redistribution of wealth”.
Some of these ideas are intriguing but Marshall barely gives them room to breathe and his conclusion feels rushed.
However he has delivered a readable primer to many of the biggest problems facing the world.