President Donald Trump’s rejection of the Trans-Pacific Partnership (TPP) has intensified debate over U.S. trade policy and its far-reaching effects.

Tariffs have been applied over the years to protect homegrown industries and target competitors who are seen as using unfair trade practices. They impose costs on both importers and exporters and had been in decline until the recent U.S.-China trade war.

Brexit supporters argue that the EU threatens sovereignty and stifles growth, while opponents counter that EU membership strengthens trade, investment, and the UK’s standing in the world.