When Stateline.org asked historian Brian Balogh of the University of Virginia why a presidential election matters to the states, he did not hesitate to retrieve an example.
"Abraham Lincoln," he replied. "His election sealed the fate of the union. If you ever wanted to pick out one example of when an election mattered to states it was Lincoln."
Not every election is that momentous, but the point is that a president makes a big difference to states in setting policy as well as tone.