WASHINGTON (Reuters) - Government watchdogs filed a complaint against Donald Trump Jr., Jared Kushner and Paul Manafort on Thursday with the federal agency that oversees elections, arguing the three violated the law by meeting with a Russian who was offering purportedly damaging information on Hillary Clinton.  The complaint with the Federal Election Commission was signed by Common Cause, the Campaign Legal Center, Democracy 21 and two campaign lawyers involved with those groups. It identified as respondents the Trump campaign and Trump Jr. Common Cause filed a complaint earlier this week with the agency. Thursday’s complaint added three attendees at the meeting: Manafort, who was Trump’s campaign manager at the time, Kushner, Trump’s son-in-law, and Rob Goldstone, who arranged the meeting. The complaint takes advantage of information disclosed in email exchanges with Trump, Jr., son of President Donald Trump, that detailed how and why the meeting in 2016 was arranged.  The Federal Election Commission is the only federal agency that can bring civil charges for violations of the campaign finance law. However, because the panel requires bipartisan agreement to move forward on any actions, critics have expressed concern that the agency was unlikely to take action.  Democrat U.S. Representative Grace Meng wrote to the Federal Election Commission on Wednesday asking it to take up Common Cause’s first complaint against Trump Jr. The organizations said in Thursday’s complaint that the emails provided evidence that Trump Jr. violated the law by asking a foreign national for something of value, which they argue the law would define as “including the fruits of paid research, hacking, or similar investigatory activity.”  “The evidence is clear that Don Jr. knew that the offer of opposition campaign research came from the Russian government, and the law is clear that giving such valuable research for free would have been a contribution to the Trump campaign,” said Brendan Fischer of the Campaign Legal Center. The complaint said that Manafort and Kushner, by attending the meeting knowing the subject matter, are also at fault.   Donald Trump, Jr. and the White House have insisted there was no wrong doing. Democratic lawmakers want the Federal Election Commission to bring civil charges against Donald Trump, Jr., saying the meeting violated the law.  The Department of Justice could bring criminal charges.  