A faction is defined as a group of people with the same interest. According to Madison, the danger that a faction poses to good government is that it acts in its own interest, not the people's interest. What is bad about a faction is that, it will try to get what they want even if it hurts others. Hope this answer helps.
The theme of the poem is basically the American Discrimination. Discrimination is basically is a term which is used to define the difference b/w two groups on the base of some qualities etc. For example the American Discrimination was between black and white people.
