Immigration policy has always been for the benefit of the nation.
What qualifies as the benefit of the nation varies wildly between libertarians and the right v. commie/socialists/progs/left. The left believes that getting more poor-ass, useless idiots on the voting rolls to overthrow western society is for the benefit of the nation. Hell, some leftists believe overburdening the system with useless people is a means to an end...as in, the end of the constitutional form of government. (see Cloward-Piven)