The conservative news network Newsmax filed an antitrust lawsuit against Fox News on Wednesday, saying Fox has sought to maintain its market dominance through intimidation and exclusionary business practices designed to stifle competition. Fox has sought to block television distributors from carrying Newsmax or minimize its exposure, pressured guests not to appear on the rival network and hired private detectives to investigate Newsmax executives, said the lawsuit, filed in U.S. District Court in south Florida. Newsmax seeks a jury trial.