Sonoma County Supervisor Mike McGuire turned down the chairmanship of the board Tuesday, saying the demands on his time are too great.

"The bottom line is that the county and the residents of the fourth district are my priority," he said after his surprise announcement.

McGuire, 34, is running for an open state senate seat, but he declined to tie his decision directly to that campaign, though he did admit that was a draw on his limited time. He said he reached his decision last week after several weeks of thought.

Instead, the board turned to outgoing chairman David Rabbitt, who was elected to an unusual second consecutive term in the position, which normally rotates among the five members.

Supervisor Susan Gorin was elected vice chair, positioning her to take the chair position in 2015. Gorin said she briefly considered putting herself forward as chair this year in McGuire's stead, but she decided she was not prepared to take the gavel yet.