After Canada failed to strike a trade deal with Washington, the president raised tariffs on some Canadian exports this week.

Trump has justified tariffs on goods from Canada, the top U.S. export market, by accusing it of failing to stop the cross-border flow of fentanyl, even though U.S. government data shows Canada accounts for only 1% of the fentanyl that enters the United States.

They claim that the country’s overall trade deficit — the sum of the U.S. trade balance with all countries — represents economic weakness and a national-security threat. But what can bilateral trade deficits and the country’s overall trade deficit tell us about trading relations and the health of the U.S. economy? Here are some facts: