NX(e)

A great picture from Menzie Chinn shows that in the world, like in the textbooks, the trade balance depends on the exchange rate.

The figure show the log real dollar exchange rate (a higher value means a weaker dollar) lagged two years (in blue), the ratio of net exports to GDP (in red), and the ratio of net exports excluding oil to GDP (in green). The last recession is shaded in gray.