Republican Rick Berg concedes to Democrat Heidi Heitkamp in North Dakota Senate race

Republican Rep. Rick Berg has conceded the North Dakota Senate race to Democratic former state attorney general Heidi Heitkamp, completing Democrats’ virtual sweep of key Senate races.

Heitkamp’s win means the Democrats expanded their majority by two seats on Tuesday. There will be 53 Democrats, 45 Republicans and two Independents in the next Senate. Vermont Independent Bernie Sanders has long caucused with the Democrats. Newly elected Maine Independent Angus King has not yet announced with whom he will caucus but is widely assumed to be planning to caucus with Democrats, as well, raising the Democrats effective strength to 55.

Heitkamp led Berg 50.5 percent to 49.5 percent percent, with all precincts reporting, according to The Associated Press.