Angus King is an independent who caucuses with the Democrats. Unlike Bernie Sanders, he is a pretty normal-seeming Democrat, not a self-described democratic socialist. What has he said about his reasons for being an independent?
King has been an independent for a long time. Initially, when he stood for Governor of Maine in '94 he said:
The Democratic Party as an institution has become too much the party that is looking for something from government
Others suggested that the real reason for King standing as an Independent was his belief that he could not beat former governer Joseph Brennan in the primary.
He chose to caucus with the Democrats in order to get onto House committees however he says:
It does not mean I have become a Democrat. It does not mean I have made a promise to anybody.
Politically, King is a centrist, and portrays himself as having a political position between the two major parties.