Riding a wave of momentum in the final weeks of the campaign, Gabe Amo, a former White House official, won the special Democratic primary election for an open U.S. House seat in Rhode Island on Tuesday.His victory makes history, putting him on track to become the first Black person ever to represent Rhode Island in Congress. The outcome is nonetheless a disappointment for the activist left, which had hoped that one of their longtime allies, former state Rep. Aaron Regunberg, would prevail.Amo, who defeated 10 Democratic rivals, will face Republican nominee Gerry Leonard in a special general election in November.But since Rhode Island’s 1st Congressional District, which encompasses the eastern half of the state, is solidly Democratic, Amo is widely expected to represent the district in Con...