Country star Sara Evans has obtained a restraining order against her ex-husband -- claiming he irreparably harmed their children by badmouthing her on Anderson Cooper's new TV show.
Craig Schelske appeared on "Anderson" back on September 20 -- claiming he lost custody of his kids because Sara falsely accused him of being a porn-obsessed adulterer.
Sara claims the interview not only violated a temporary injunction she obtained against Craig back in 2010 -- blocking him from bashing Sara in public -- it also "caused and will continue to cause irreparable harm to the children."
On September 21 -- a day after the interview aired -- Sara filed a request for a restraining order to block Craig from making further statements about their divorce proceedings. A judge signed the order the same day.
A source close to Craig tells us, "This is a violation of his First Amendment rights, and he won't take it lying down."
It's the latest in a bitter custody dispute for the couple that has been going on for months.
According to the papers filed earlier this year, Schelske accused Evans of surrounding them with drugs and alcohol. He claims he's been on tour with his country singer ex before -- and "has first-hand knowledge that the children are exposed to inappropriate conduct, spend little time with Evans], and are placed in a party atmosphere with excessive drinking and drug use."
Schelske adds, in the past Evans has even "encouraged and condoned underage drinking."
The couple divorced in 2006 after 13 years of marriage.