12:03 PM PT -- Defense attorney Mark Eiglarsh came on "TMZ Live" Tuesday to weigh in on the Crumbley case -- and he told us this case will serve as a precedent for years to come on this type of scenario.

According to him, this is going to remind parents that they are, in fact, responsible for their children's behavior -- and that moms and dads need to know their kids inside and out in order to prevent another tragedy like this from ever happening again.

Ethan Crumbley's parents are going to prison just like their son -- 'cause a judge just sentenced them to more than a decade behind bars, this after their manslaughter convictions.

James and Jennifer Crumbley learned their fates Tuesday in a Michigan court, where a judge handed down 10-to-15-year prison sentences to each of them. That was the maximum sentence they were facing ... and Hizzoner threw the book at them. They're getting 858 days credited for time served.

Remember ... the convicted mass shooter's mom and dad were both criminally charged with involuntary manslaughter after their son shot and killed 4 people at his high school in 2021.

Their guilty verdicts were historic ... marking the first time parents had been found criminally liable for their children's behavior. Prosecutors argued that both James and Jennifer could've prevented Ethan from going on a shooting spree ... as there were clear warning signs.

Jennifer had testified during her trial that James was responsible for hiding the gun that Ethan ended up using ... but in the end, a jury found each of them equally responsible for the deaths.

Prosecutors had asked a judge to impose the stiff sentences -- noting they hadn't shown any remorse over their actions ... or lack thereof to help prevent the awful tragedy.

The Crumbleys, meanwhile, requested supervised release, asking to be placed on house arrest -- arguing they'd already served more than enough time for the crime they were convicted of. Clearly, prosecutors got what they asked for.

As for Ethan himself ... he's already been sentenced to life in prison without the possibility of parole. He was only 15 years old when he carried out the shooting, and is now going on 18. His folks have been behind bars for the past 2 years as their cases have played out.

Now, they'll be serving even more time.