WASHINGTON — Neither congressional race in Maine this year will feature a contested primary, since the filing deadline passed Monday for Democratic Reps. Tom Allen and Mike Michaud and their Republican challengers. But Michaud's 2nd Congressional District race in northern Maine could still become a three-way contest if a prospective candidate runs as an independent. Allen, of Portland, who is in his fourth term, faces a challenge from Charles Summers, who spent eight years as state director for U.S. Sen. Olympia Snowe, R-Maine. Allen, a member of the Energy and Commerce Committee, has won previous contests easily, with 64 percent...