What is the most elastic state in the country?

[Sir Mohamed]

I'd say WV. Between 1996 and 2016 it swung from 51% Dem to 68% GOP. And it's more Dem at the state level (or has been in recent years). However, I doubt Dems will win the state ever again in a presidential election.

Otherwise: IA and OH.

[Sir Mohamed]

Based on 538's list, they are all smaller states.  Though I disagree with where they placed states on their chart, I would agree that elastic states would tend to be smaller.

Maybe FL is the 'most elastic' of the large states?

FL would be one of the least elastic states in the whole country, both parties have very high floors in FL.   You almost never even see down ballot races go much below 46% in either party, except maybe for Bill Nelson.

Agreed, all FL races on federal and state levels were close except Bill Nelson so far. There is a 45/46% floor for both sides. The most elastic big state is probably OH.