Money should not be diverted to either. The money diverted to foreign nations rarely if ever produces the stated benefits. It certainly has not produced stability in the regions referenced above.
When you say money for taxpayers...that is a somewhat a myth as well. If we simply gave money to Americans, the velocity of money would increase and the corresponding value of that money will in turn decline proportionately. In simpler terms, if we gave everyone a million dollars, a million dollars would not be worth anything anymore.
The money spent overseas has somewhat a similar impact, as this contributes to national budgetary deficits, which devalue the purchasing power of our currency when deficits are rising. The overall money supply is something that is monitored closely by the Federal Reserve, as a too rapid expansion or contraction of the money supply can be dangerous. Whether or not they do an adequate job of that is open for debate. But it is amazing how many people don't understand the inflation phenomenon, and why we can't just give people money created out of thin air.