Actually there is no argument because he relies on correlation. (For a moment, let us dismiss the grotesque cynicism that motivated this e-mail) Correlation has no explanatory value whatsover.
For instance, there is a well-known positive correlation between the size of a person's hands and mathematical aptitude. However there is no causal relationship between the two. The missing explantory variable is, of course, age.
The original e-mail is pure, unadulterated BS
dressed up as quasi-serious economic analysis for the easily-deceived eye. My guess is that it was written by a college upperclassmen or beginning grad student with a little bit of knowledge of econometrics, forecasting, or stats and a dislike for the United States.
B747-437B, Frankly I was disappointed and surprised that you posted this stuff as a basis for a discussion. Your posts are usually consistently good. I would have guessed that you saw through this immediately.