What contributes to a state's elasticity?

[TJ in Oregon]

It has to do with the demographics of each party's base in the state. The Midwestern and New England states tend to have higher elasticities because they have a large number of moderates and independents, and in the case of many Midwestern states, the partisans they do have aren't as extreme. In contrast, states like Mississippi or Oregon have very few persuadable voters and the results are largely determined by demographics.

[TJ in Oregon]

If a state is racially homogenous. NH and IA have among the highest elasticities. Independents also mean that OH and FL are elastic.

The inhomogeneity isn't the reason why states with a lot of minorities tend not to be very elastic; it's that Republicans get 15% max of the black vote. Thus states with a lot of whites will have more potentially persuadable voters.

If you look at states with a lot of Hispanics and/or Asians, they can end up being rather elastic (eg. New Mexico and Hawaii).