If borrowing to pay for the resulting excess of imports over exports means that our foreign debt keeps increasing faster than gross domestic product, our creditors are likely to get nervous.

Excess nitrogen and phosphorus nutrients due to large quantities of feed imports, can lead to problems with manure disposal and pose a potential pollution risk.

But for periods when imports temporarily exceeded exports, the country needed a stock of dollars or some other acceptable "hard" currency "in reserve" to pay for excess imports.