Former Arizona Attorney General Terry Goddard is officially becoming a candidate for the Democratic nomination for secretary of state.

Goddard's campaign said he's filing candidacy papers Thursday with the Secretary of State's Office. Goddard had said previously he'd run for the office.

Goddard is a former Phoenix mayor who ran three times for governor unsuccessfully, most recently in 2010. He served two terms as attorney general from 2003 through 2010.

Arizona's secretary of state is the state's top election official but also is the first in line to become governor if that office becomes vacant in the middle of a term.

Arizona does not have a lieutenant governor.