FILE - In this June 17, 2014 photo, Seth Mazzaglia gets ready to leave the courtroom during his first-degree murder trial in Strafford County Superior Court in Dover, N.H. The New Hampshire Supreme Court decided that the details of Elizabeth "Lizzi" Marriott's sexual history should remain private after her rape and murder. Mazzaglia was convicted of the murder and is serving a life sentence, but argued the trial court should’ve allowed him to introduce evidence about Marriott's past. (AP Photo/Jim Cole, File)
FILE - In this June 17, 2014 photo, Seth Mazzaglia gets ready to leave the courtroom during his first-degree murder trial in Strafford County Superior Court in Dover, N.H. The New Hampshire Supreme Court decided that the details of Elizabeth "Lizzi" Marriott's sexual history should remain private after her rape and murder. Mazzaglia was convicted of the murder and is serving a life sentence, but argued the trial court should’ve allowed him to introduce evidence about Marriott's past. (AP Photo/Jim Cole, File)

As attorneys debated the merits of a new trial for the man convicted of raping and killing a female University of New Hampshire student, their disagreements hinged strongly on one word: consent.

While the defense team for Seth Mazzaglia argued to the state Supreme Court on Wednesday that Lizzi Marriott died accidentally in a sex game gone wrong, state prosecutors stood firm, saying the facts clearly show that Mazzaglia raped and strangled her in Dover in 2012.

Strafford County Superior Court jurors sided with the prosecution in 2014 in convicting Mazzaglia of first-degree murder. However, Mazzaglia’s attorney says evidence excluded by the trial court colored jurors’ opinions of the 19-year-old UNH student – and ultimately their verdict.

Specifics to support their arguments are restricted from public view, per the state’s rape shield law. Oral arguments Wednesday were also censored, as attorneys could not speak of the sealed record on Marriott’s sexual past.

Attorney Christopher Johnson, who is representing Mazzaglia in his appeal, told the Supreme Court that jurors in Strafford County got two distinct and vivid impressions during the 23-day trial. The first impression was of an “extraordinary and admirable” young woman and the second of a sexual encounter that was “dangerous and brutal,” he said. “The concern here is the juxtaposition of those two vivid impressions would create cognitive dissonance – it would crowd out the possibility that Miss Marriott could possibly have any interest in (such) activity.”

Johnson spoke Wednesday about a third impression obscured by the restrictions on evidence: He said the lower court erred in barring witness testimony referencing prior statements Marriott made about her openness “to specific sexual practices,” and thereby her propensity to engage in the sexual activity in question.

But the private sexual history of a rape victim is confidential under New Hampshire law. The state’s rape shield law prohibits a defendant from introducing evidence about a victim’s sexual past as part of his defense in court.

And in recent months, state prosecutors, counsel for the Marriott family and victims advocacy groups have fought tirelessly to uphold those protections in the face of Mazzaglia’s appeal.

Assistant Attorney General Geoffrey Ward said Wednesday that claims about Marriott’s sexual past have no bearing on the case at hand and say nothing about whether Marriott consented to having sex with Mazzaglia. Her private sexual history, including any alleged statements she made years before her death, are presently and should always be off limits, he said.

“This court has said explicitly that consent on one occasion does not equate to consent in the future,” Ward said.

Should the Supreme Court rule in Mazzaglia’s favor and grant him a new trial, Ward said the consequences would be far-reaching and could render the rape shield law meaningless. That’s because – for the first time – a victim’s statements about his or her prior sexual interests would be admissible evidence, he said.

“The reason why the rape shield law was enacted in the first place is to make sure that a victim’s sexual history was not put on trial and to encourage the reporting and to encourage victims to see the process through,” he said.

Amanda Grady Sexton, public policy director for the New Hampshire Coalition Against Domestic and Sexual Violence, echoed that point in a statement after the hearing. She said the defense team used “a deeply flawed understanding of sexual consent” by arguing that Mazzaglia’s “conviction should be overturned based on speculation about Lizzi Marriott’s past.”

“This is victim blaming at its worst. Lizzi was lured into a situation where she was raped and murdered; nothing about her alleged past thoughts or expressions would have changed or contributed to this,” Grady Sexton said.

After battling for several months to keep the sexual history of their daughter confidential, Melissa and Bob Marriott are hopeful that the resolution of the case is near, and that the Supreme Court will uphold Mazzaglia’s conviction, their attorney, Rus Rilee said by phone Wednesday afternoon.

He noted the couple is relieved to have reached this point, but found oral arguments to be “extremely painful and difficult.”

Mazzaglia is serving a life sentence for murder without the chance of parole. His appeal was formally submitted to the state Supreme Court at the conclusion of Wednesday’s hearing, although the justices may not issue a ruling for several months.

(Alyssa Dandrea can be reached at 369-3319, adandrea@cmonitor.com or on Twitter @_ADandrea.)