Cmdr. Peter Lamont could send Watts to jail, order him thrown out of the Canadian Forces in disgrace or demote him.
Watts was found guilty in December of unlawfully causing bodily harm and negligent performance of military duty in the training accident north of Kandahar City.
Cpl. Josh Baker, 24, died when an anti-personnel mine loaded with 700 steel balls peppered a platoon on a practice range three years ago. Four other soldiers hit by the blast were seriously injured.
The prosecution argued during the trial that Watts, who was the platoon commander, didn't enforce safety standards and abdicated his duty as leader when he handed over responsibility to Warrant Officer Paul Ravensdale.
The defence argued that Watts's blameworthiness is on the low end of the scale, since no one could have predicted what his lawyer called a "freak accident."
"He should only receive a very minimum sentence ... a reprimand," defence lawyer Balfour Der said after a sentencing hearing last month.
"Maj. Watts was found guilty, but it's as marginal as it can be," he added.
"I'm fairly confident that under these circumstances he's not going to get anything more than a reprimand."
But the prosecution said Watts should spend time behind bars.
"There's little evidence of remorse from Maj. Watts or that he has accepted responsibility for his actions," Maj. Dylan Kerr argued during the hearing.
Kerr suggested a message must be sent about Watts's part in the accident. He has called for 18 months in jail as well as outright dismissal or a demotion of two ranks to lieutenant.
The court martial heard that the range was divided into four training sections that day. The first two tests of the anti-personnel mine went off without a hitch. But when the second firing occurred, the ball bearings fired backwards, hitting Baker and the others.
Videos show several soldiers, including Watts, standing around watching the test. They are not inside armoured vehicles or standing behind them for cover as set out in safety regulations.
Der said a harsh sentence could destroy his client's life. Watts works as a senior firefighter with the Calgary Fire Department as his regular day-to-day job.
"Jail would likely end his career as a firefighter. It would end his career as a military officer."
Watts's commanding officer, Maj. Christopher Lunney, pleaded guilty in September to negligent performance of duty, was demoted to captain and given a severe reprimand.
Ravensdale, who has since retired, was convicted last week of unlawfully causing bodily harm, two counts of breach of duty and one count of negligent performance of military duty. He has yet to be sentenced.
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