Supporters of Democratic presidential hopeful Bernie Sanders are frustrated by the support his rival is getting from the party establishment, and some are taking it out on superdelegates.

Bernie Sanders

Maine has five of the superdelegates who can support whoever they choose, regardless of the outcome of state caucuses on March 6.

Three already have committed to Hillary Clinton. One of them, Maggie Allen, says she's received a barrage of hateful emails and phone calls from Sanders' supporters.

Aroostook County's Troy Jackson is Maine's sole superdelegate who's supporting Sanders. He's pressing for a resolution that all Maine superdelegates support the winner of Maine's Democratic caucuses.