As Donald Trump draws the world closer to a trade war and the United Kingdom tears itself apart over Brexit, it’s easy to feel bleak about the future.

British economist and writer Philippe Legrain, in New Zealand for a week-long tour, argues we shouldn’t give in to “the politics of pessimism”.

Speaking to Newsroom, Legrain draws a distinction between the negativity which drove voters to support nationalist causes like Trump or Brexit, and the “justifiable pessimism” of those fearing the consequences of that support.

He describes the US President as “a giant wrecking ball”, laying waste to the established rules and norms which have governed the modern world for decades.

“We’re in a really worrying period in world history where the liberal international order that was created after World War II is basically over, and we don’t know what is going to take its place.”

Legrain says Trump may win re-election despite his disastrous presidency so far, thanks to the strong economy he inherited. Even if he is booted out it’s unclear how much can be unwound.