Jamelle Bouie tracks the movement:
Democrat Max Rose ran as a moderate in his successful bid for the 11th District of New York, which includes Staten Island and went for Donald Trump in the 2016 presidential election. Rose emphasized his military service—the 31-year-old is a veteran of Afghanistan—and distanced himself from national Democratic leadership, going as far as saying he wouldn’t support Nancy Pelosi for speaker of the House. He rejected Medicare for all.
But his “centrism” reflects a Democratic Party that has moved to the left since it last held the House of Representatives. Rose’s “top priorities” for health care include a “public option” for insurance and a Medicare expansion that lowers the eligibility age to 55. Had he served in the 111th Congress, which passed the Affordable Care Act, this position would have put him to the left of the median Democrat and in line with the views of the House Progressive Caucus. While progressive candidates may have lost races on Election Day, Democratic voters have clearly moved to the left, and they expect their candidates to do the same.