San Diego school-board president Shelia Jackson has filed a statement of intention to run for the Fourth District seat on the county board of supervisors, currently occupied by Ron Roberts. The election is next year, and rumors persist that Roberts will step down before his term is up to allow the board, made up of Republicans, to appoint a like-minded successor. Scuttlebutt has it that the list of likely GOP candidates for the appointment includes D.A. Bonnie Dumanis and Marla Marshall, the longtime aide to ex-Sheriff Bill Kolender and now an aide to Sheriff William Gore. That would leave out Jackson, a Democrat with strong backing from labor unions. Jackson has voted to adopt a controversial “project labor agreement” requiring district construction projects to be built by union labor, and she is an ally of the teachers’ union in its fight against layoffs. Observers note that Jackson gave notice of her intent to run for supervisor six days after the June 30 cutoff date for disclosing campaign donations made during the first half of the year, meaning she won’t be reporting the identities of contributors and the amounts they gave until next January 31. In an interview this week, Jackson said her candidacy was still in the exploratory stage, but she would begin raising money for a possible campaign. And Roberts can’t be counted out quite yet. Late last week he filed his own intention to run statement.… Though it was probably just coincidence, billionaire Qualcomm founder Irwin Jacobs gave $5000 last week to the gubernatorial campaign of Democratic San Francisco mayor Gavin Newsom, a day after American Idol’s Ryan Seacrest kicked in $10,000.