The smaller the society, the fewer probably will be the distinct parties and interests composing it . . . the more easily will they concert and execute their plans of oppression. Extend the sphere, and you take in a greater variety of parties and interests.

– James Madison,
The Federalist Papers

What is the main idea in this passage?

In a small society, few citizens participate in government.
A more diverse society allows more interests to be heard.
A smaller society is more likely to protect against oppression.
A larger society is less diverse and has fewer interests.

A more diverse society allows more interests to be heard.

The main idea in this passage is that a larger and more diverse society allows for a greater variety of parties and interests to be represented and heard.