The division of power between the united states federal government and the states which compose the union of the united states demonstrates the principle of:

The Constitution of the United States is the central instrument of American government and the supreme law of the land. For 200 years it has guided the evolution of governmental institutions and has provided the basis for political stability, individual freedom, economic growth, and social progress.

it's no easy i swear it's hard

explanation: we can only guess at how our actions may be perceived in the future. doing something really big like killing lots of people, saving lots of people, affecting the lives of lots of people is a sure fire way of being remembered in historical records. we can also make a difference in the history records by being a small influence on something bigger, whether that is as a civil servant, scientist or artist.

of course you could argue that we all affect history just as tiny cogs in a   bigger machine.

if you mean how do people influence our opinions of things which have already happened, then simply by writing a book which looks at things form a different perspective and trying to convince people that this perspective is more accurate or truthful. people do it all the time i.e. richard the third was a terrible or was he? plenty would disagree, it's just that their views aren't the most widely known.n: