During trade wars, 2 or more countries are limiting (or prohibiting) the flow of goods of service that is made from the other party. This tend to lead to a reduction in the overall target market and decrease in Net export (which will also lead to a decrase in Gross Domestic Products)
For example, according to the research conducted by Moody analytic, Trade war with China cost United States around 300,000 of potential jobs and a reduction of 0.3% from the overall GDP.
