In Rhodesia, the insurgency began with random, roadside attacks. From there, they escalated into sabotage and farmhouse raids. At the same time, there was political terror in the cities, often using firebombings with Molotov cocktails thrown through windows, bombings, and occasionally shootings.
Riots transitioned into a rural insurgency, and from a small insurgency, to a full-blown guerilla war.
It will begin with isolated incidents. Cops will be attacked and the unhinged public will take it as a sign, sort of how rioting/looting is contagious, that it's now okay to engage in this behavior. This will expand independently as people snap, then mass media notice may make it go “viral.”
We now have two gun attacks on ICE, 2 presidential assassination attempts, Charlie Kirk, and tons of anti-deportation riots and interference.
Desperate, irrational, and criminal people will start the ball rolling, but once desperation comes to everyone’s door and the media coverage blows up stories of “resistance,” the idea will take off. The numbers don’t have to be large, but just large enough to encourage the crazies and radicals.
This could also be framed by the left, immigrant communities, minorities, etc. as street justice or revolutionary acts. Rather than strike back at harder targets, like banks or politicians, police become an easy representative for the government.
A Robin Hood idea will take hold that it is morally justifiable to attack police. People will use the background events as license to exercise their personal grievances or fantasies.
The scary part of this is the normalization of violence against police to stop bank actions will metastasize into revenge attacks for all sorts of perceived injustices. From targets like police and politicians, it will expand to other political "enemies" from councilmen to even neighbors with another viewpoint.