The interesting part about the above map is the nuance that does not adhere to partisan regions:
States that have passed exchange bills tend to lean Democratic, but it’s by no means a clear dichotomy. Both Nevada and California passed exchange bills under Republican governors;Mississippi and Idaho have, over the past few weeks, become increasingly aggressive about setting up exchanges.
Conversely, not all Democratic-controlled states are moving. Delaware and Rhode Island’s state governments are both controlled by Democrats. Neither has moved exchange legislation. Even here in D.C, an exchange bill has sat in committee since its introduction in February.