The thorny question of whether Britain should unwind a decade of estrangement from the European Union is resurfacing as the Labour Party starts to imagine a future beyond Prime Minister Keir Starmer. Two key figures have emerged as potential challengers after a series of political body blows that have left Starmer’s leadership in crisis, and the spectre of rejoining the EU was creeping back into the debate. Wes Streeting, who resigned from Starmer’s government as health secretary last week,...