Pacem in Terris §106

¹⁰⁶ And among man's personal rights we must include his right to enter a country in which he hopes to be able to provide more fittingly for himself and his dependents. It is therefore the duty of State officials to accept such immigrants and—so far as the good of their own community, rightly understood, permits—to further the aims of those who may wish to become members of a new society.