container for the thing contained

A seamless task, when masons laid the wall
no corner where a side abuts a side.
A single surface circumscribes the hall;
the Oval Office leaves no place to hide.
E pluribus, aspiring to be one
who build each other, rather than compete
but knowing the job's never wholly done
a metaphor in plaster, made concrete.
The staatsbund Kant had hoped would end all war
inspired a league of thirteen colonies
but we've lost sight of what this Union's for
our parties brook no higher loyalties.
Among the stuff Trump threatens to tear down
enlightenment's experimental crown