The lawsuit, first reported by The Hollywood Reporter, was filed in court in the Western District of Missouri late Wednesday.
Lawyers from the law firm of Lathrop & Gage LLP argued that Robin Carnahan misused footage of Wallace's Jan. 15, 2006 interview of Blunt, and deems Carnahan's video a "smear ad."
Although the network's parent company News Corp. gave $1 million donation to the Republican Governors Association earlier this year (one of the largest single donations to any American political party this cycle), it wants viewers to know its not getting involved in the Senate race.
"FNC is a news organization that has not endorsed a candidate in the 2010 Missouri senatorial race. The value of its news reporting is based in part upon the public's faith in the accuracy and integrity of those reports," the suit says. "The Carnahan Ad is designed to make it appear as if Wallace - a trusted journalist - is instead speaking as a campaign operative."
A YouTube version of the video has been pulled because of a copyright claim by Fox News.
From the suit:
In a smear ad against political rival Roy Blunt, Defendant Robin Carnahan for Senate, Inc. usurped proprietary footage from the Fox News Network to made it appear - falsely - that FNC and Christopher Wallace, one of the nation's most respected political journalists, are endorsing Robin Carnahan's campaign for United States Senate.
The lawsuit is embedded below.