President Donald Trump has homed in on trade deficits resulting from pacts such as the North American Free Trade Agreement as the root of America's economic challenges. But in a world without NAFTA, the United States and Mexico would revert to trading with each other based on the World Trade Organization's Most Favored Nation tariff levels for both countries. It is important to identify which sectors would see minimal change without NAFTA and which would see a disproportionate impact due to a significant tariff increase and large trade volumes. The sectors experiencing the highest impact would logically put the most energy into lobbying for the preservation of NAFTA. The United States exported $292 billion in goods to Mexico in 2016. The biggest industries that export to Mexico (heavy machinery, electronics, energy and plastics) would only see slight increases in tariffs and would thus be marginally affected.