We hear a lot about trade deficits, but repealing trade agreements will not fix the arithmetic. If a country consumes more than it produces, it will import more than it exports. Federal deficit spending, a huge and continuing act of dissaving, is the big culprit. Control that, and you will control trade deficits.

Imposing tariffs on trade within North America would affect the demand and price of final goods imported by the United States from Mexico and Canada. It would also affect the demand for intermediate goods produced in the United States that are exported to Mexico and Canada for final assembly. In a 2010 study, nearly 40 percent of United States imports from Mexico were United States value-added, while about 25 percent of United States imports from Canada were United States value-added.

Top categories for United States exports to Mexico and for United States imports from Mexico overlap: vehicles, machinery and electrical equipment. North American products cross borders often before reaching the consumer. Disrupting supply chains would have consequences not only for Mexico and Canada but also for United States exports.

North American countries should be working toward greater integration in energy and national security. When Nafta was first negotiated, the energy sector was excluded because Mexico’s oil, gas and electricity industries were controlled by the state. But in recent years, Mexico opened up the sector to competition and foreign investment. The three countries should push toward an integrated North American energy market; that will favor the energy independence and national security of the region.

The United States, Mexico and Canada should secure the true border of North America: Mexico’s southern border. One argument from the Trump administration to repeal Nafta is illegal immigration from Mexico to the United States and the effect it has on its workers. The truth is that net migration from Mexico to the United States has been zero or even negative for roughly 10 years. If the United States wants to do something about illegal immigration, it must pay attention to the condition of northern Central America.