If you want to dig into the law and history that surrounds presidential impeachment, HeinOnline has built an entire online research collection. You’ll need to first sign in with your NYLS network credentials.

Here is a brief description from HeinOnline:

Organized by the four affected presidents, this collection brings together a variety of documents both contemporaneous and asynchronous to each president’s impeachment, presenting both a snapshot of the political climate as each impeachment played out and the long view history has taken of each proceeding. Congressional Research Service reports round out a general discussion of presidential impeachment and a curated list of scholarly articles, external links, and a bibliography provide avenues for further research on this topic.

Hein will continue to add material to the library as it develops.