Steve McLaughlin, who led the Association for the Help of Retarded Citizens for 24 years, has sued the group’s board of directors for wrongful termination, breach of contract and slander. McLaughlin claims that two board members in particular launched a “malicious vendetta” against him that led to his leaving in September. McLaughlin was earning $157,000 — plus use of a vehicle and $15,000 in deferred compensation — in the first year of a five-year contract approved in 2006. He is seeking millions of dollars in damages.