Europeans confront a new, zero-sum world

Simon Tilford, deputy director of the London-based Centre for European Reform, a pro-European Union think-tank, says that people voting for Brexit in June’s referendum took for granted that the US would continue to underwrite the global trading and financial systems as well as global security.

These, Mr Tilford points out, are what economists call global public goods. Among the characteristics of public goods is that the marginal cost of allowing another person to benefit from them is zero. Take a publicly funded bridge. If one person uses it, it doesn’t prevent another from doing so. In fact, both efficiency and welfare are maximized if as many people as can comfortably use it, do so.

"Trump is no economic liberal and does not appear to understand how global institutions and norms crafted by the US serve its interests," Mr Tilford wrote. "He may only last one term in office, but the UK cannot afford to assume that Trump’s presidency is just a temporary hiatus before normal service resumes."