It has often been said that Presidential nominees do not think of their Vice Presidential nominees as replacing them in office, because of death. No one likes to think about that unpleasant, potential possibility.
But Presidential nominees NEED to think about that, because it should be the most important factor involved in selection of a running mate.
When one looks at Presidential elections since 1960, it is clear that Vice Presidential nominees fit into two categories: those ready on “Day One” to take over the Presidency, and those NOT ready on “Day One” to take over the Presidency.
Those Ready on “Day One” (15)–10 Democrats and 5 Republicans
Henry Cabot Lodge
Lyndon B. Johnson
Hubert H. Humphrey
George H. W. Bush
Those NOT ready on “Day One” (6)–1 Democrat and 5 Republicans
William E. Miller
The selection of the Vice Presidential nominee is the first, and in many ways, the most crucial decision a Presidential candidate makes. In that regard, the Democrats have been dramatically more careful than the Republicans!