Indiana has no port to speak of and would have to cross foreign land or airspace to export her products. That alone would render secession economically stupid on a monumental scale.
A state seceding is like a 12y/o kid saying he wants to leave the family.
Convince Gary that they can be an "international" port and they just might vote for
Regarding leaving the family thing, I'd say Texas is about 17...it would be tough, but if dad didn't beat 'em to death for trying they could probably make it.