...One nation, invisible.
( ... ( ( ( ( One nation ) , ) invisible ) . ) )
(ROOT (NP (: ...) (NP (CD One) (NN nation)) (, ,) (NP (JJ invisible)) (. .)))
An invisible nation.
( An ( invisible ( nation . ) ) )
(ROOT (NP (DT An) (JJ invisible) (NN nation) (. .)))