Depends on the population and is against illegal immigration. All for legal and controlled immigration.
When a country population grows too fast, the demands overtakes the supply. The result is an increase in prices aka inflation to make the supply harder to acquire. Not to mention the competition in getting a stable source of income. It's one of the reasons a 4 year college don't mean shit nowadays.
So for the overpopulated and unstable US, I think immigration should temporarily cease in order to better stabilize the country and when some control is acquired, let the immigration flow.