[High School US History/English] Women's Rights Research Paper Ideas

I'm trying to kill two birds with one stone. In my US History class I have to write a research paper. In my English class I have to write an argumentative research paper.

A suggested topic I received was to argue that the 19th century Women's Rights movement was important to United States history.

What would I argue against this topic? What makes it important instead of not important? I need help finding main ideas, good sources, and counterarguments.