Yes, it has always had the power, but rarely acted on that power, until this century (although it did restrict immigration of various groups, depending on the political whims of the populace, chinese comes to mind). Government has gotten bigger to regulate all of this and as the regulations increase, so does the size of government. The US government used to pay for advertisements in Europe to try to get more immigrants to come here. Europeans governmetns were upset because many of their citizens were leaving the freedom suppressing countries of europe. Of course, I don't suggest government steal any more of our tax money to enact such a a progmam...
I don't propose open borders as terrorists need to be stopped. I'm in favor of moving the military towards the borders and building a fence. However, I'm also in favor of letting anyone who can get here on their own free will into the country.
Would you ever stop the flow of people into this country? At what point would there be too many people?
Can't you see what unchecked population growth (India, China, Africa) does to a nation?
Not me. Economic migrants have no respect for the country or its culture. They are here to make a buck to enrich their own country.
I say let anyone who escapes communism freely into the country. Economic migrants need to be stopped at the borders.