We shouldn't block non-citizens from coming to the United States because of the concern about terrorists. Although letting people in to United States increases the possibility of terror, it also brings many benefits. First of all, numerous of people who seek to move to US from different countries have a purpose of education. They want to have better and further education in US so that they can contribute to the society. In fact, the government knows that a lot of students from other nations are extremely intelligent and have a potential to become respectful persons who will develop the US as well as the entire world. Second of all, by opening the door of immigration, US can have better and advantageous position in an international commerce. The reason why US is called "a land of opportunity" is that people from all around the world come to the united states and make the opportunities together. In my opinion, together we make better world. Terrorism needs to be taken care by the Federal Bureau of Investigation, not the immigration center. Once again, we should let non-citizens in to the United States because they will contribute to the development of the society.