In 2018 the district became the first in the United States to have the winner decided through ranked choice voting, after a referendum in 2016 changed Maine's electoral system from first-past-the-post to ranked choice. Incumbent representative Bruce Poliquin won a plurality of the first preference votes. However, the second and third preferences from two independent candidates flowed overwhelmingly to Jared Golden, allowing him to win with 50.6% of the vote once all preferences were distributed.
In US presidential elections, most states give all the state's electoral votes to the candidate that wins the statewide popular vote. This is a type of winner-takes-all voting. Maine and Nebraska instead use the congressional district method, where the winner in each of the state's congressional districts gets one electoral vote, and the statewide winner gets an additional two electoral votes. Since Maine introduced this system in 1969, Maine's second district voted the same way as the entire state of Maine for every election until 2016.
The boundaries of the District are open for reconsideration in light of population shifts revealed by the decennial US Census. Until 2011, Maine's constitution provided for the state to reapportion the Congressional districts based on census data every ten years beginning in 1983, which would have meant that the state was next due to consider redistricting in 2013. However, a federal lawsuit filed in March 2011 led to a requirement that Maine speed up its redistricting process. Maine state legislators approved new boundaries on September 27, 2011.