cash-for -foreign car sales

I just read an article about the well thought out cash-for-clunkers program. It seems that the program is a real boost for Japanese car sales.
Wouldn’t you think that a plan to boost car sales would be directed towards American car sales since it is the American tax payers that are paying for the scheme.
As usual, the congress has put out another half thought out program. Sure, a sizable chunk of their cars are made in the United States, but Detroit is still not reaping the benefit that it could be getting.
Per the article, the top models bought since the scheme began on July 24 are Toyota Corolla, Honda Civic and Ford Focus, all small sedans. Three of the top five are Toyotas.
Sure car sales have increased across the board at the detriment of the American tax payer, but wouldn’t it be better kept on our shores rather than sending more tax payer money abroad.