The Latest: GOP rep says he won election 'fair and square'

PORTLAND, Maine (AP) — The Latest on a lawsuit challenging Maine's voting system (all times local):

3:10 p.m.

Republican U.S. Rep. Bruce Poliquin says he won re-election "fair and square" and says he has a duty to fight Maine's new voting system that he says is unconstitutional.

Poliquin spoke to reporters Tuesday in Augusta after joining a lawsuit that seeks to overturn Maine's ranked-choice voting system, used for the first time last week in U.S. House and Senate elections.

The congressman told reporters in Augusta that "not addressing this important constitutional matter would be completely irresponsible and not doing my job." He called the system that lets voters rank all candidates on the ballot "convoluted" and "chaotic.