From the linked article:
"In the United States and Australia, mandatory minimum sentences have been utilized for much of the past few decades. Many states are now revisiting them, recognizing that mandatory minimum sentences do not protect society, they do not rehabilitate individuals, and they do not generally contribute to the well-being of others. They do, however, vastly increase the cost of the criminal-justice system."
>mandatory minimum sentences do not protect society,
>they do not generally contribute to the well-being of others
False, by definition of incarceration. Specific deterrence (isolating the criminal from society) protects the innocent.
>they do not rehabilitate individuals,
Perhaps not, but the flawed assumption is that the individuals can be rehabilitated irrespective of sentence. If not, there are two options:
1) Permit them to prey on others.
2) Isolate them.
>vastly increase the cost of the criminal-justice system
Either we pay to incarcerate, or we pay insurance premiums and risk being victims. I'll go along with the socialists on this: I pay taxes for government to solve the problem so that I don't have to deal with it.
General deterrence works on honest people; the spectre of embarrassment and punishment is the help an honest man sometimes needs to stay honest. It should not be expected to have any effect on the criminally minded.
Rehabilitation is possible for honest people and non-habitual criminals - people who suffered a moment of weakness sufficient to overcome general deterrence. It should not be expected to have any effect on the criminally minded.
For the criminally minded, there is only specific deterrence.
In summary: whether mandatory minimums provide general deterrence or rehabilitation is irrelevant. They meet the third objective, specific deterrence, which is sufficient. The only demonstrable flaw of mandatory minimums is that people who can generally be deterred or can be rehabilitated (in other words, basically honest people) can be swept up in the net. To mitigate that, we can distinguish between first and subsequent offences.