Was it really ever a debate to begin with, though?

If you were one of the few who referred to a Michigan resident as a "Michiganian" you're officially overruled. Governor Snyder signed Senate Bill no. 562 which makes it state law that

"MICHIGANDER" MEANS A RESIDENT OF THE STATE OF MICHIGAN.

It also will remove any references of "Michiganians."

The law is part of a 13-bill package to modernize laws that are related to historical markers.