Food for thought: If you look at the history of civilizations, it's apparent that no country was immune to immigrants or invasions. Countries' demographics changed. Cultures and ideologies came and went, sometimes as the result of hostile takeovers, sometimes as a consequence of time. Why, in this day and age, do we think the dynamic is preventable? You only own that which you hold a deed to. Your heritage is no guarantee of your status, eligibility, benefits, or security. Walk into a Medicaid office, as my Alzheimers-stricken mother did at age 79, and they'll make the application process unsurmountable, while they bend over backwards to assist a recent immigrant who can't speak a word of English!
While we're aware of the physical border crossers, the overstayed guests, and family loopholes (friends posing as family members), we're seemingly unaware of the more influential invader: foreign investors. You might lose a few hundred high-paying jobs to PhD-carrying "dreamers", but entire companies and their resources are being bought by foreign investors, some of whom are shells for their countries' governments. Even undeveloped real estate is being snatched up. America is for sell if the bid is high.
Personally, I don't resent any immigrant--naturalized or not--as long as they contribute to our economy. The humble, but hard working, food picker is just as valuable as the engineer. The welfare-seeking socialist immigrant needs to get the boot. There are "families" who have one job holder--or own an unprofitable business--and intentionally stay at the poverty level to exploit social services. The welfare benefits they receive are comparable to what they would have existed on in their native country; however, the income is dependable here.