US President Donald Trump has introduced 25 percent tariffs on Mexico and Canada, and a 10 percent tariff on China - delivering on one of his key election promises.
A day after signing the order President Trump acknowledged Americans may find themselves paying the costs of his new measure.
But what actually how do tariffs work and why are they so controversial?
Emile Donovan speaks to former diplomat and Executive Director of the New Zealand International Business Forum Stephen Jacobi.