There is certainly precedent for this. For example, Police Battalion 101 needed to be able to keep order while they marched people off to the forests where they could kill them. That is exactly what they were tasked to do and that is what they did. For more details of this critical need, Google the term “Einsatzgruppe”. See what the left really has in mind.
SL Tribune editorial: LEOs need ability to kill large #s of people..
So why did libs complain about Kent State? Lots o’ dead in Ohio.
Just one article of many.