If President Donald Trump orders the U.S.-Mexico border closed, as he again threatened on Tuesday, the impact would be devastating. Trump wants to stop the flow of illegal immigration, but his chaotic and impetuous response won’t fix the problem and will cause new ones.

Trade in goods and services totaling $1.7 billion flows through the border every day. As the United States’ third-largest trading partner, Mexico is partly responsible for vehicles Americans drive, clothes we wear, electronics we use and food we eat. Our companies depend on Mexico for parts and goods they need, and our farmers supply Mexico with corn, soybeans and more.

The last time the border was partially closed, after the 9/11 attacks, backlogs and economic losses were significant. If the border were shut now, there would be a sudden interruption in the U.S. supply of auto parts, which could halt production within a week. Forty-four percent of our fruits and vegetables come from Mexico. If the border closes, expect prices on produce to rise.

Beyond that, 5 million Americans have jobs connected to commerce at and travel through the border. And there would be ripples through other industries and the stock market. Little would remain untouched.

Even if Trump tries for a full or partial border closure, logistical complications and legal challenges could make it difficult. And since there’s no way to close the entire border, it’s probable that illegal immigration would continue.

The spike in migrant families crossing the border is a humanitarian problem that requires comprehensive solutions. This isn’t one of them.