How did other countries respond to American tariffs? What effect would that have?

Other countries respond to American tariffs by creating their own tariffs or refusing to do business with America. The effect this could have is a hurt exporters by making their products more expensive. They could struggle to maintain their sales, which could cause profits to fall and, potentially, the country's economy to shrink. Alternatively, exporters could decide to cut their prices to maintain sales, but this too could shrink their profits.