Do you really need to make it more difficult to study in the US? If a person decides to get an education in this country and leave their own country behind, looking for a better future, you should be helping them, not putting barriers to their personal development. I bet that if you make it easier for students who have completed a degree in the US to become citizens many of them will stay and help the economy by boosting the job market. Not only that, but they are more likely to create businesses and more likely to commercialize patents. Let them become productive and highly skilled citizens instead of blocking their chances of success