The Russians, using American built planes and supplies. Read up on
the 'Lend - Lease' program where America supplied ammunition, weapons,
fuel, food and medicine to the Allies during WWII. England couldn't
get their Merlins off the ground without the special high octane
gasoline available from a Texas refinery. Then read about the amount of
Penicillin, Magnetrons, and other items that no one else could build in
the needed quantities. America supplied over half of the ammunition
used by the Allies during WWII
Finally, read the MIT 'RadLabs' series of books to see how much of
modern electronics was developed by the US during WWII. it is over 750
MB of scanned material.
<
http://cer.ucsd.edu/~james/notes/MIT OpenCourseWare/MIT Radiation Lab/>