I think the USA really underestimates the number of foreign nationals that are spying for their countries in our military, government, top corporations, and colleges. There are spies from every country for sure but China has by far the largest campaign of espionage against the US and we wonder why they "progressed" so quickly in terms of technology. We need to do like Germany and really tighten the number of visa's and green cards issued from these countries until we reach a manageable level to keep an eye on them.