BUCHAREST — When a mayor of a small Romanian town casually mentioned in an interview that she had voted in favor of a referendum that sought to ultimately ban same-sex marriage, it unleashed a maelstrom that now threatens to become a key issue in elections next year. The problem was that Elena Lasconi was not a far-right populist or traditionalist but a member of the progressive Union to Save Romania (USR), the only parliamentary party in Romania to explicitly oppose a 2018 referendum that sought to redefine marriage as a union between a man and a woman and limit LGBT rights. She was also running for a seat in the European Parliament next year. The referendum eventually failed due to a low turnout, but five years on LGBT rights have stalled and remain a divisive and touchy issue in the Eastern European country.