What kind of example?

Shall we turn off their food, water and utilities, build a wall around the city, and shoot anyone who attempts to escape? This was tried in Warsaw in the 1940s.

Shall we use armored bulldozers and flatten the place? This has been tried recently in the Palestinian territories.

Shall we build a group of re-education camps in Kurdistan and send the entire population there? And shoot anyone who attempts to escape? This was tried in China in the 1960s, and again in Cambodia in the 1970s.

Shall we just build camps without the "re-education" component, and send them all there? This was tried in the Soviet Union in the 1960s and 1970s.

Shall we just kill all the boys and men? (There were no women in the picture.) This was tried by the Egyptians, in the Book of Exodus.

Shall we drop a nuke on the city? The only two times that was tried, it was done by us, with years of horrific carnage in the run-up to the bombing, and a certain amount of ignorance about the weapons as a mitigating factor.

Shall we use conventional bombs on the civilian population? This was tried in the 1940s, throughout Europe and east Asia.

Surely it wouldn't be a good idea to just beat them up and imprison everyone we can lay hands on, because the escapees will go to other locations to set up shop, and tell tales against us.

One assumes the city is already under martial law.

The concept of justice that I was taught apprehends suspects, tries them, and then punishes those convicted of wrongdoing. Those are the examples, not the city and all its inhabitants. The punishments under martial law can be, and often are, severe, but they are informed by court proceedings with strict rules of evidence.

The concept of justice is not served by punishing a whole community for the crimes of the few. That's vengeance. It turns the people thus treated into objects used to make a point, and the people doing the treating into thugs. Are we to stand for justice, or are we not? Are we only Americans while we are at home?

The problem with examples is, there are always survivors.