America’s power and reach depends not just on what you can see, from military hardware to the software of social media, but on that which lies out of sight. Take the unseen network of fibre and wires that the US employs to weaponise its financial system against both enemies and allies.

That, at least, is the claim of foreign policy specialists Henry Farrell and Abraham Newman whose book, Underground Empire, tells the tale of America’s efforts to control the world economy by seeking out and manipulating a subterranean communications network of “tunnels and conduits”. Some of this effort is intentional, some happens by chance. In the words of the authors, by taking charge of key intersections of the network, “the US government could secretly listen to what adversaries were saying to each other or freeze them out of the global financial system”.

That story is captivating — the stuff of thrillers. Their thesis that this work continues today as part of a secret and elaborate plot, less so.