Battles of attrition are messy affairs for all parties involved and tend only to occur once other options have failed. Donald Trump seems to want to make them his preferred economic policy. The U.S. president on Saturday imposed tariffs of 25% on Mexican and most Canadian goods - as well as a fresh 10% levy on Chinese imports - sparking tit-for-tat retaliation and global market ructions.

In executive orders issued on January 20th, the day of Mr Trump’s inauguration, it said that it could respond by doubling taxes on citizens and firms from any offending countries. These orders displayed his advisers’ talent for unearthing obscure statutes that serve their goals: the law that allows the doubling of taxes on foreigners has been in place for nine decades without being used.

President Trump’s tariffs on Canada, China and Mexico could upend U.S. trade. These nine charts show what’s at stake, what comes next and why it matters.