Elaborate on this a little
It is helpful because the grid can help pinpoint the exact location on the map.
It actually mean't that the US had should own the lands between the Atlantic and Pacific.
I believe the answer is integrity versus despair
Integrity in this context refers to the ability for late adults to accept that we're all going to die in the end.
Late adults who failed to accept this fact will tend to have irrational paranoia, depressed, and eventually fall deeper into despair.