Portland Mayor Ethan Strimling addresses outgoing City Councilor Jon Hinck during a ceremony Monday at City Hall to bid farewell to two outgoing councilors and swear in their replacements. City Manager Jon Jennings is at left. Ben McCanna/Staff Photographer A power struggle at Portland City Hall that boiled over into public meetings over the past two weeks has been raging behind the scenes for the past year, according to internal communications obtained through a public records request. And it appears to be far from over. Mayor Ethan Strimling has been pushing to expand the authority of the elected mayor, clashing with the city manager and challenging the city’s top attorney and her interpretations of the city charter. At one point, the City Council privately decided to spend more than $21,000 for a second opinion about the scope of the mayor’s authority from an outside lawyer, but even that has not settled the issue. At another point, City Manager Jon Jennings sought advice about how to file a formal complaint against Strimling for violating the charter, after the mayor sought information from city staff without first contacting the manager’s office. The struggle, however, has been playing itself out mostly behind closed doors and in emails, and only recently was aired in public meetings and interviews with the media.