John Tyler, the Accidental President – by Edward Crapol

  More detail than I wanted.

Basic story – undone by slavery, of which he was a avid supporter. Achievements: Border with Maine/Canada, trade agreement with China, annexation of Texas, Tyler Doctrine in Pacific (which eventually lead to annexation of Hawaii).

Believed expanding the borders would keep nation together, and eventually would lead to the end of slavery (weird idea). First Vice President to become President, played a large role in setting precedence that VP would become Pres. for rest of term. Constitution was unclear on that point. 

He was a Whig, but big on “states rights”, like his idols Jefferson and Madison. Caused him to become very unpopular within his own party. Was not even nominated for a run at a second term.