Answer and Explanation:
The theme of the poem is that American society is not a perfect society, but a society that is walking, a long and difficult journey, striving to always be the best it can be. She says that for this journey to be successful, society must have not only unity, but patience, kindness, justice, humility and hard work.
It reinforces that the American people are able, but it will not be easy, to establish a perfect union, where everyone can climb the hill.
