One's own body is projected into and equated with a body politic. "Illegal immigrants" are not-self cells, penetrating into the self, violating porous boundaries. 

Open borders = The immigrant "creeping in" to one's own body, generating an hysterical response. Projected into national life, hysteria becomes paranoia. Paranoia is a hysterical response to the "other" imagined to be violating the boundaries of one's body.

The nation or body politic is a double of the self; a double of one's own body.