Other forms: ombudsmen
In the U.S., your congressman is considered your unofficial ombudsman or the state official who investigates and makes sure the government is acting in the best interest of its citizens.
The word come directly from the Swedish ombudsman, meaning "legal representative." An ombudsman is a legal representative, often appointed by a government or organization to investigate complaints made by individuals in the interest of the citizens or employees. Usually this is a state official appointed to oversee an investigation of complaints about improper government activity against citizens.