U.S. Political History Seminar: Civil Liberties in the United States

The library catalog and WorldCat use Library of Congress Subject Headings. The list of authorized subject headings is available online. However, you can start with keyword searches to gather some relevant titles, then look at their subject headings to discover the official terms to use.

Be aware that subject headings are often not "natural language."  For instance,

Freedom of speech 

is a subject heading, but the heading for the right to assemble is

Assembly, Right of.