How does Kennedy use parallelism to emphasize the potential for potential for American society to become more divided?

Kennedy uses parallelism to emphasise the potential for American society to become more divided by bringing the focus on the actions of the American people and the choices that the Blacks can harbour against the Americans.

Explanation:

According to him it will happen if the wrong choices were to be made. According to him black people can also have hard feelings for the white people too.

It was predicted to be Black people will fight against the White Americans.