Based on analysis of the vote, ABC News projects that former Vice President Joe Biden will win the Maine primary, securing 10 Super Tuesday states.
Polls open at 6 a.m. ET and close at 8 p.m ET.
For the first time in twenty years, voters in Maine headed to the polls rather than to a caucus site. At stake are 24 delegates for the Democrats, and 22 delegates for the Republicans. So far, Biden and Vermont Sen. Bernie Sanders' have earned at least seven delegates each.
In 2019, legislators not only voted to switch to a state-run primary system, but they also signed legislation for Maine to become the first state to enact rank-choice voting. Under a ranked-choice system, voters order candidates from their first to last choice.
In 2016, Sanders' New England roots helped him topple Secretary Hillary Clinton, 64.2% to 34.5%, in the Pine State's primary. In 2016, President Trump lost the primary to Texas Senator Ted Cruz, 45.9% to 32.6%.