Study some history and look at the numbers to see why "Buying American" and supporting domestic manufacturing is so important to our national security. We will loose on a global scale (in more ways than one) if we don't have a strong domestic industrial base.
Military production during World War II
There is an interesting video series from ABC in 2011. If you have time to watch these, it will be eye opening. Our small purchase decisions over time can have a big impact on our nation's economy. Here is Part 2 below.