The Fifth and Fourteenth Amendments have been interpreted as a guarantee of (1) procedural due process and (2) substantive due process. You should focus on the latter, which relates to the issue of whether the government is acting in excess of its authority.

+1

I did a quick google and was smacked in the face with info.

Do your own homework. You can start with the wiki page.

Come back if you need clarification after doing so, but don't be lazy.

And what court cases were determined based on the due process clause. Thanks!

From my understanding Thomas basically is trying to upend due process