Wikimedia Commons The Daniel-Johnson Dam in Quebec, Canada, is the largest arch and buttress dam in the world. For the past month Maine lawmakers have been considering a slate of bills that could sideline Hydro-Quebec from an upcoming referendum on Central Maine Power's highly controversial transmission project. The legislation centers on whether a company wholly owned by the Quebec provincial government should be allowed to spend money to influence Maine voters in the campaign. But the debate is actually bigger than that, and it has drawn the attention of national groups seeking to beat back the tidal wave of corporate election spending that was unleashed by the U.S. Supreme Court's decade-old Citizens United decision.