Jordan Linn Graham of Kalispell pleaded guilty to second-degree murder in the death of her Cody Johnson just eight days after their marriage, The Missoulian reported.
While Graham's attorneys are seeking a sentence of 10 years in prison followed by five years of supervised release, prosecutors are seeking a life sentence for Graham.
In a 28-page court filing, prosecutor Zeno B. Baucus said Graham was unremorseful after her husband's death.
After the incident, Graham left the scene in Johnson's car, text messaged friends and wrote upbeat posts on Facebook, the document said.
"Such behavior is consistent with someone that does not appreciate the seriousness of her actions and has the mental wherewithal to engage in similar conduct again in the future," Baucus said.
Baucus also said prosecutors believe Graham planned her husband's murder.
"Cody ultimately experienced a surprise that evening, but it was one from which he did not return," Baucus wrote.
Defense attorney Michael Donahoe argued that Johnson's murder was an accident.
"By her guilty plea to second-degree murder it has been conclusively established that the defendant committed an extremely reckless but nevertheless unintentional act," he said.