Trade between nations or cross borders is to exchange for goods, materialized items or service rather than to make money (paper notes that need backed by production and by creditibilty of the trading nations). For example, a country has produced extra more cars for its domestic market, but is short of energy like oil. One obvious choose for this country to trade its cars with other nation with rich oil to sustain both economic healthy growth.
Globalization is a process linking nations via easily conducting mutual benefiting business or trade cross borders.
So, why does some country need to impose a trade war against another country? The answer is simply to balance the trade deficite. A question arises why the deficite occurs. It seems the deficite is bad, but it actually most benefits the nation with trade deficits - it uses its money (paper) to buy or freely obtain goods from the trade surplus nation! Think about it!
Stop doing such stupid things to export goods to exange for money!
People live depending upon food, housing, car, service, etc., on goods, rather than on money!