Although we have begun publishing inventories to the APS Archives in the Philatelic Literature Review, this collection continues to grow. While I was at WESTPEX last month, David Grossblat donated an 1893 American Philatelic Association ballot cover. (The American Philatelic Society was called the American Philatelic Association until 1908.)
The ballot itself is not included, but based on the Globe, Ariz. postmark I suspect it is from Morris Klein, the only member listed in the 1893 directory from Arizona.
Prior to this addition, the oldest election-related item in the APS Archives was a ballot from 1897. (Click to view full size.)