The article explores how trade between countries affects differences in business taxes. It shows that when trade is easier, the size of a country's market becomes less important in determining how much businesses are taxed. The researchers studied data from 26 OECD countries from 1982 to 2004 and found that countries with bigger markets tend to have higher business taxes, but trade integration weakens this connection. This means that as countries trade more with each other, the differences in business taxes between them become less dependent on the size of their markets.