In what can only be described as a legal quagmire and a political nightmare for public officials, the city’s Ethics Commission decided Wednesday to launch an investigation of nearly 40 City Council members and candidates who violated a local election law.The commission determined the unprecedented broad investigation was the only way to stop people from filing individual complaints against each violator. Nearly every member of the City Council, including Mayor Sam Liccardo and other longtime politicians, violated the city’s election code by failing to properly report late campaign contributions. The widespread problem was discovered after Councilman Manh Nguyen was investigated in June for missing or late campaign filings. The commission, without knowing about the dozens of other violators, slapped Nguyen with a $10,000 fine.But Nguyen and other council members blamed the city clerk for doling out bad advice that led to confusion about filing deadlines. City Clerk Toni Taber acknowledged the error, apologized multiple times and urged the commission to dismiss Nguyen’s $10,000 penalty.