Why is this a partisan issue?

Daylight Saving Time is up for vote in the Indiana assembly today. Aside from the inanity of trying to pass a bill that you know to be unconstitutional, it seems strange to me that this bill represents a "divisive issue among Indiana lawmakers and their constituents." Which party opposes and which supports? Maybe it's geographically divisive, with the Cincy suburbs wanting the state to join Eastern, and the Evansville and Chicago areas wanting the state to join Central. That seems implausible because Chicago and Evansville would more than cancel out Cincy, leaving the rest of the state (who really shouldn't care one way or the other) to garner the majority to pick a time zone and stick with it.

I can't wrap my head around why this is such a huge issue. I'm beginning to think that the parties are simply fighting for the sake of fighting. Fix the damn bill and pass it already.