Apparently, the Democrats have had control of the legislature in Tennessee for 40 years, a streak that ended this year.
So, with a 50-49 majority, the Republicans thought it was up to them to name a new chair. Being Republicans, they nominated/crowned a conservative for the post.
However, the Democrats had their own plan and nominated a candidate of their own -- a moderate Republican.
Well, the Republicans didn't think the Dems would succeed in their plan. After all, Republicans wouldn't vote for someone the Democrats chose, would they?
Well, when your name's on the ballot, you HAVE to vote for yourself...
(hat tip: JM Bell)