There is a US federal Law called the Hatch Act which prevents federal employees or elected officials from using their official position to campaign.
Tennessee has a law called the Little Hatch Act. This law prohibits all Tennessee State and Local elected officials from using their official position to influence elections of any kind. Specifically:
"or to otherwise use such person's official position or employment to interfere with or affect the result of any regular or special primary election conducted within the state,"
Linda Noe points to this letter in support of a local sales tax increase in Hamblen County. This appears to me to be a clear and obvious violation of the Little Hatch Act. The letterhead says "Hamblen County Government", below it says "from the courthouse", it lists all local officials in their official capacity and uses a government email address. Any reasonable person would see this as an official county government communication.