IN ANNOUNCING Monday his decision to seek a fifth term on the D.C. Council, Jim Graham (D-Ward 1) sought to dismiss issues about his ethical conduct as “old business. It was before my last election.” That claim overlooks that voters knew little about that conduct when they reelected him in 2010, just as we knew little about it when we endorsed him. Now that more facts are known about his abuse of the public trust, they will be important for voters to consider.

Mr. Graham’s actions in 2008, regarding the city’s lottery contract and a Metro development project, became a matter of scrutiny only in 2012. A report by the D.C. Inspector General, released on Jan. 20 of that year, aired allegations that Mr. Graham, while on the Metro board, tried to get a businessman to withdraw from the development project in exchange for support of the businessman’s separate bid for the lucrative lottery business.

An independent investigation by a law firm hired by the Washington Metropolitan Area Transit Authority board cited incontrovertible evidence of Mr. Graham’s misconduct. In an exhaustive Oct. 11, 2012, report, the investigation concluded that he had breached the authority’s standards governing conflict of interest and impartiality. D.C. ethics officials reached a similar conclusion regarding the D.C. code of conduct, and the D.C. Council in February reprimanded Mr. Graham and stripped his committee of some authority. We said then that Mr. Graham should resign. He said he didn’t think he’d done anything wrong.

Instead of campaigning early and raising money to scare away potential challengers, as incumbents often do, Mr. Graham formed an exploratory committee and was late to announce his candidacy, The Post’s Aaron Davis reported. No doubt Mr. Graham recognizes that his chances are much improved if the vote is split. Three challengers are now set to face Mr. Graham on April 1 in the decisive Democratic primary; they each need to ask themselves if they will best serve Ward 1 residents by staying in the race. However many remain on the ballot, the incumbent’s record will be a focus of debate. Mr. Graham’s proven ethical lapse is not the totality of his record in 15 years as a council member, but neither is it irrelevant “old business.”