Former Maine Gov. Angus King — an independent — will announce a run for retiring Sen. Olympia Snowe's (R-Maine) seat in the Senate. Two sources close to King told the Kennebec Journal he would announce his campaign Monday night. King did not respond to messages seeking confirmation. A popular two-term governor and professor at Bowdoin College, King has a history of working with both parties and a demonstrated appeal to the state's large swath of independent voters. About 390,000 registered voters in Maine belong to neither major party — more than are registered as either Democrats or Republicans.