Ticket balancing is the practice of picking a running mate according to what strength he can add to the presidential candidate in the election. Rarely is a person picked solely because he would make a talented, or even competent, substitute president. For our purposes, we will define a ticket as the presidential and vice-presidential candidates of a given party. The presidential candidate is usually referred to as the head or upper half or the ticket. The vice-presidential candidate is usually referred to as the bottom or lower half of the ticket.
Ticket balancing goes back to the very beginning of our republic.
The second place on the ticket is filled based on how much the choice can help the ticket get elected, regardless of how incompetent the person may be. It has led to some stunningly poor vice presidents and potential vice presidents. In the very beginning, it was a simple matter of balancing north and south geographically. In 1796, John Adams of Massachusetts ran with Thomas Pinckney of South Carolina. Thomas Jefferson of Virginia ran with Aaron Burr of New York.