Prime Minister Mark Carney on Friday said Canada could offset the effects of any U.S. tariffs by removing internal trade barriers and that he aimed for free trade within the country by July 1, after meeting provincial and territorial leaders.

Since U.S. President Donald Trump first threatened to place massive tariffs on Canadian goods, the country has been embroiled in a whirlwind back and forth with its biggest trading partner. Here's a quick look at how tariffs are set under normal circumstances.