China. Looking back at what my CIS colleagues Dan Cadman and Jessica Vaughan and I have written over the years about foreign students, it is clear that only China has created serious national security problems for us (see here, here, and here). It, alone among the three, has created and funded an organization to keep their students in line politically (the Confucius Institutes) and it has, because of the size of its student delegation created more DHS-documented drop-outs than any other nation. We have also touched on the hard-to-handle question of academic cheating by some of these students.
We do not hear about any significant theft of our government or business secrets by migrants from India or Mexico (there may be some of this, however); that appears to be a Chinese specialty.
A more rare, and more expensive, way to enter the United States on a government mission is the use of the laxly administered EB-5 (immigrant investors) program. This used to require an investment of $500,000 (now $900,000) in a DHS-approved, but not guaranteed program, and it leads, years later, to a set of green cards for the investor and his or her family. While most of the fraud in the program is private-sector in nature (with many Chinese as the victims), the only alleged misuse of the program for spying purposes among the three nations known to me has featured a Chinese investor buying under-water surveillance devices.
India. The Indian establishment has used the H-1B program, for college-grad foreign workers, to enhance its private sector — rather than the public-sector approach of the Chinese.
In a way that I think is without parallel, India has created a bunch of India-based firms that serve as middlemen for U.S. companies wanting to use relatively inexpensive Indian workers in the H-1B program to cut costs, and deny jobs to U.S. workers. These are rent-a-programmer operations, such as Tata and Infosys, which provide IT talent, almost all of it on the H-1B program, to U.S. firms. These are the so-called outsourcing companies that use a high proportion of the H-1B slots; when hiring, they employ 97 percent to 99 percent of their workers from their own country.
In fact, the discrimination by these firms is done on more than nation-of-origin lines, it includes bias in favor of young, male workers from the southern (and more Hindu) part of the nation, as we and others have reported. There have even been news accounts that suggest that the Indian caste system has taken hold in some hiring decisions by these Indian firms.
And though there is no known study of the subject, we keep hearing from U.S. citizens in the IT world that most of the human resources people in the industry seem to have Indian names; some of these are in the United States (probably on H-1B visas) and some are doing their work, I am told, from India.