But what if it's mostly domestic spending? The money spent for salaries flows in whatever those individuals need/desire to spend (groceries, barber shop, you na

But what if it's mostly domestic spending? The money spent for salaries flows in whatever those individuals need/desire to spend (groceries, barber shop, you name it). The part of the trillion dollar injected in any economic activity in a closed system stays in that system. (The part of that sum that is used to buy imports is another thing, although I guess it's far more complicated to properly account for) Honestly, every time I think about this my mind just melts; I'll be really glad if somebody can clearly explain where is the catch.