The liberty of every American citizen freely to come and to go must frequently, in the face of sudden danger, be temporarily limited or suspended. Th… - Hugo Black

For me, the only correct meaning of that phrase is that our Government must proceed according to the 'law of the land'—that is, according to written constitutional and statutory provisions as interpreted by court decisions.

[I]t is true that [the provisions of the Bill of Rights] were designed to meet ancient evils. But they are the same kind of human evils that have emerged from century to century whenever excessive power is sought by the few at the expense of the many.

[...] all legal restrictions which curtail the civil rights of a single racial group are immediately suspect. That is not to say that all such restrictions are unconstitutional.