The Democratic mayor of Anchorage will throw his hat in the ring today for the Alaska Senate seat Ted Stevens has held for 4 decades, the Anchorage Daily News reports. Stevens, one of the Senate's most notorious pork producers, has been reelected easily 7 times, but is now under federal investigation for corruption. Mark Begich will face three other Democrats in a primary; the 84-year-old Stevens will run against two GOP challengers. (More Alaska stories.)