Mayor Bill de Blasio (photo: Ed Reed, Mayor's Office)

With the impending departure of the head of the city’s campaign finance regulatory body, good government advocates say Mayor Bill de Blasio must be careful about who he chooses to fill the position as the city heads into an election year.

“The chair of the campaign finance board is probably the single most important player in government ethics,” said Gene Russianoff, senior attorney at the New York Public Interest Research Group, a government reform organization.