Canada can only go so far in responding to new tariffs imposed by US President Donald Trump given the mismatch in size between the economies, Prime Minister Mark Carney said.

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.

Trump's use of tariffs as a bargaining tool is likely to erode other countries' faith in the US as a place to do business