This is both past and future relevant.
When the Constitution of the United States was established, even post riders took several weeks to travel from Washington to Northern Massachusetts (now known as Maine) and Georgia. As the nation expanded, it took even longer; roads to the west were even worse. How long a communication delay could a republic under the US Constitution or a similar made of government thrive under long term? (California was soon bound tighter to the USA with the Pony Express, then the telegraph.) How far flung a USA could be managed without the telegraph? I’m referencing full states, not territories that don’t participate in national elections, etc.
And in the far future, some science fiction has extra-solar states of the USA, sometimes with weeks of communication lag between the extra-solar state and Washington. Could the modern USA function if several states were weeks away in communication? Or would the arrangement become too cumbersome, and need to be revised?