When I try to rename an existing Category to a previously deleted Category's name, I get a vague error about the rename failing.
A peak in the wp_terms table reveals that Categories deleted from Manage Categories aren't actually deleted - they still exist in the database. Meaning I cannot add a category with the same name again.
This is not the behavior I was expecting.
My question is: How can I readd deleted Categories or rename an existing Category to something that was deleted?