Victim Cherice Moralez killed herself while the case against Rambold was pending. Rambold was 47 at the time of his crime.
Under state law, children younger than 16 cannot consent to sexual intercourse.
"Rambold continues to perpetuate the myth that a 14-year-old girl should bear responsibility for her sexual victimization by a 47-year-old teacher," Plubell wrote. "The law, though, rightly defines her as blameless."
Rambold's attorneys have argued that the original sentence from state District Judge G. Todd Baugh was appropriate. In a brief submitted to the state's high court last month, they urged justices to find that Baugh had acted appropriately.
Citing Moralez's statements in interviews with law enforcement recorded before her death, Rambold attorneys Jay Lansing and Nancy Schwartz said there was "no rational basis" to conclude a 14-year-old could bear responsibility only as the offender in a rape case. A 14-year-old victim can bear responsibility, too, the attorneys suggested.
The interviews are under court seal and have not been made public.
Lansing could not be reached for comment Thursday. He has turned down all previous interview requests.
Victim Cherice Moralez was a freshman at Billings High School when she was raped. Rambold was her business teacher. She committed suicide in 2010, an act her mother said was driven largely by the rape.
The girl's death took away the prosecution's main witness, and Rambold initially avoided prosecution under a deferred prosecution agreement that included sex-offender treatment.
He violated the agreement by having unauthorized visits with relatives' children and having a sexual relationship with an adult woman, according to court documents.
That re-opened the case and led to the August sentence from Baugh of 15 years in prison with all but one month suspended. Rambold was released in September.
Baugh unsuccessfully sought to impose a longer term after coming under criticism for saying during the sentencing hearing that the victim "appeared older than her chronological age."
Montana's Judicial Standards Commission has asked the Supreme Court to censure Baugh for imposing an unlawful sentence and blaming the child victim.
The panel investigated the case after receiving hundreds of complaints about the judge.