Killing is what the military does.
Trump has declared that the protests are lead by terrorist "Antifa".
The police were already gassing, shooting and brutalizing protesters.
I don't know what other conclusion to draw about what "overwhelming force" and "dominating" would mean in this context besides murdering people.
> disperse, detain and ultimately deter lawbreakers
It could mean that you do a show of force so strong that the opposing side gives up. In this case he was probably referring to putting so many policemen/national guard out there that they could disperse and detain all of the looters and rioters. This would likely prevent further looting and rioting as people would see that they would likely get caught.
So any troublemakers would think twice about trying to hit an area to sew chaos (looting, rioting, setting property on fire, etc.)
Militaries are also trained for peacekeeping missions. It’s not all about trigger happy gun toters.
If it’s an all out rebellion that’s different. I don’t see a ruby ridge or Waco incident coming, but maybe you do.