The most potentially influential politician you've probably never heard of, former two-term Maine Gov. Angus King, on Tuesday officially entered the race to replace retiring moderate GOP Sen. Olympia Snowe.
King, 68, an alternative-energy entrepreneur and supporter of President Obama, filed more than 6,000 signatures with Maine's secretary of state to ensure his place on November's ballot.
He'll run as an independent, as he did for his successful gubernatorial runs in the 1990s.
