Immigration is what has made America what it is today. Without immigrants there would be no Americans other than American Indians. As Americans we enjoy living in one of, if not the most diverse and multicultural countries in the world.
In my opinion, immigration is that with screening and intense background checks, immigrants should be allowed into our country. I do feel that only so many people from other countries should be accepted per year and there should be exceptions for those coming from war torn countries. But, there has to be a process that these people would have to go through. To deny immigrants from coming here for a better life would simply be wrong and hypothetical.
Food for thought: What would America be without immigrants?