The New York City office of public advocate needs to go away forever. But it's the beast that refuses to die -- a nagging and expensive nuisance.

Consider: The Board of Elections right now is preparing for an Oct. 1 citywide runoff for the Democratic nomination to the office -- pitting state Sen. Daniel Squadron of Brooklyn and Manhattan against Councilwoman Letitia James of Brooklyn, two fine candidates.

But the annual budget for the advocate's office is $2 million. The cost of a runoff is $13 million. And with no other contested races on the ballot, turnout will likely be light.

For two decades this has been an office in search of a mission. So far nobody's found one.

It's essentially a vestige. Until 1990 the office was held by the City Council president, who ran citywide and did the council's bidding on the Board of Estimate.

When the Charter Revision Commission whacked the Board of Estimate in 1990, it should have axed the council president's job as well.

But no. Politicians persuaded the commission to keep the president around as . . . well . . . maybe an official who could foster governmental openness and champion the cause of bureaucratic decentralization.

Predictably, the office had little impact.

So in 1993 the council changed its name to office of the public advocate and charged its occupant with serving as an ombudsman for residents who need help getting vital services from municipal agencies.

True, Public Advocate Bill de Blasio -- the winner in last week's Democratic mayoral primary -- has used the position to shine a light on troubling gaps in health care and other pressing problems.

But how does that differ from what the City Council's 51 members should be doing? More than anything, the office helps those who aspire to higher office build citywide name recognition along with a political base.

New Yorkers do need to vote in the Oct. 1 runoff. If the job exists, the best person should hold it. But it was time to pull the plug on this office decades ago -- and it still is.