system
Given the following post, respond as if you're commenting on Reddit:
human
[Dark Knight trilogy] What exactly is the Dent act and how does it work?

I've watched these movies so many times and I just don't get it. What is it? Why does it lock up the entire mob? Why would Harvey being a criminal make the law invalid? The people are still criminals aren't they?
gpt
The Dent Act effectively allows for criminals deemed to be part of a mob family to be arrested and denied parole and then given higher sentences than they would have been otherwise given. 

In other words, it creates a new category of justice where if you are deemed to be part of organised crime then you are punished more severely and denied several basic parts of due process. So there are normal criminals subject to one set of rules and "mob" criminals subject to another - who decides who is in each category? The same people prosecuting them. 

So it worked by throwing the entire mob in jail, denying parole and sentencing them harshly for any crime they could find they had committed, keeping them off the streets for as long as possible. 

The act was only passed in the wake of Harvey Dent's tragic death, when public opinion was sufficiently anti-mob that they accepted this kind of two-tier justice system. If Harvey had been found to be a criminal then public opinion would likely have swayed quickly back the other way, this would have been seen for the violation of human rights that it was and it would likely have been repealed.