Even using the flawed assumption that a system is a city, when criminals go around in tanks, the military answers them. The police might hold the line, but they're not going to just go "grab the bazooka out of the trunk" and take care of it.
In the stereotype land of FL, Space is an Ocean. Police handle commerce, civil stuff, and low scale pirates- Xenos, most Liberty Rogues, Bundschuh, LWB, etc. When the more militaristic "pirates" come calling- Outcasts, Corsairs, Red Hessians- that's the military's job. The police will still hold the line, but when it comes to cracking warships, the military gets funding for a reason. The pirate factions with caps are effectively hostile nations- would you send the NYPD or Coast Guard to repel a Russian invasion? Hell no. They might help, but they wouldn't be your mainstay forces.
![[Image: SCRAgenderheuristics.png]](http://i530.photobucket.com/albums/dd343/sovfalcon/SCRAgenderheuristics.png)