Mayor de Blasio & aides visit a shelter (photo: Michael Appleton/Mayor's Office) This is part two of a three-part series, De Blasio and Homelessness: A New Progressive Mayor Wrestles with an Old Social Problem, by Peter Nasaw and Thomas J. Main. [Jump to Part One: The Challenge of Homeless Policy] Part Two: Setbacks and ResponsesThe new administration was set back when Barrios-Paoli, a seasoned administrator and voice of moderation, left just 20 months after she had joined with much fanfare.