Tennessee’s state Elections Commissioner, Mark Goins, has decided to list Republican nominees first on general election ballots, starting next month in a special election. See this story. In the recent past, Democratic nominees have been listed first.
It is somewhat likely that state law, giving discretion to the Elections Commissioner, is unconstitutional. The 7th circuit long ago ruled that it is unconstitutional to let county elections officials enjoy discretion as to which parties to list first on the ballot, and U.S. District Courts in Oklahoma and New Mexico made similar rulings.