The girl told investigators she had sex with a teacher at her school 15 to 20 times, most recently in March 2011.
Slane said the girl testified at a January preliminary hearing for Nash that she consented to all of the acts and acknowledged taking his phone and initiating contact with him.
The attorney cited a March 29 decision by the Arkansas Supreme Court to overturn a man's conviction on four counts of second-degree assault with a student who was 18, saying both of them had a constitutional right to privacy because they were consenting adults.
“They basically ruled that the state couldn't prohibit them from having sex,” Slane said. “They stuck down the law as it was written because it was too broad.”
Nash, who is free on $50,000 bail, resigned from Western Heights last year. His trial date is set for Oct. 29. Slane said he expects Oklahoma County District Judge Jerry D. Bass to rule on the motion by the end of September.
Both sides are expected to appeal the judge's ruling to the court of criminal appeals, which could delay Nash's trial indefinitely.
“Statutes passed by the legislature are presumed to be constitutional and like every other motion filed by criminal defendants we'll argue this one in court,” First Assistant District Attorney Scott Rowland said Tuesday.