What is the meaning of a quote by Walt Whitman as follows [closed]

I am trying to make sense of the following which I assume is a reference to the conflict with the American Indians. Specifically, what do the pronouns "they" and "it" respectively refer to in the following quotation?

What is any Nation, after all — and what is a human being; — but a struggle between conflicting, paradoxical, opposing elements — and they themselves and their most violent contests, important parts of that One Identity, and of its development?

Walt Whitman 1875 copied from a wall in a Texas museum

Solution 1:

When in doubt about pronoun elements, a quick test is to refer to the nearest preceding noun or noun phrase that could agree with it in number or function. By that test, use this:

What is any Nation, after all — and what is a human being; — but a struggle between conflicting, paradoxical, opposing elements — and they themselves and their most violent contests, important parts of that One Identity, and of its development?

By this test, "they" refers to elements and "its" refers to that one Identity. So, plug them in and see whether they make sense:

What is any Nation, after all — and what is a human being; — but a struggle between conflicting, paradoxical, opposing elements — and (these) elements themselves and their most violent contests, important parts of that One Identity, and of that One Identity's development?

In this case, both readings work. Within a nation or a person, the elements contest, and this contest is a part of Whitman's "One Identity."

If one of the pronoun/noun substitutions didn't work, you would need to go further back to try to find a noun or noun phrase that fits better. Sometimes no perfectly fitting word or phrase will work. This means that the pronoun refers to something ambiguous (it could refer to two or more NPs), remote (it's in another sentence), or vague (it's unclear if it refers to anything in-text). (ThoughtCo has more on "Faulty Pronoun Reference.")