We know how much we pay to service our debt (public and private) owned by foreign entities, and we know how much we receive on the assets we’ve accumulated abroad. And it turns out that the net income number is positive, relatively stable, and has been rising over a long period of time. What the paper concludes from this information is that the real value of America’s investments abroad has risen faster than our liabilities have accumulated, and that the apparently massive accumulated trade deficit is just an accounting fiction. It’s not that we mortgaged Alaska to buy a Lexus or a Mercedes. It’s that we mortgaged Alaska to buy Eurodisney, with a little money left over to buy a Lexus or a Mercedes; and Eurodisney has proved so profitable that if we sold it we could easily pay off the Alaskan mortgage.