The article looks at how trade between countries affects differences in business taxes. It shows that when countries trade more, the size of their markets becomes less important in determining how much they tax businesses. The researchers studied data from 26 OECD countries between 1982 and 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.