There are a number of purposes in this article. Let us look at three of the main purposes.
First, the article is meant to inform us of some of the problems with American prisons. The authors say that America imprisons more people than other countries. It says that American prisons fail to rehabilitate people and that the rates of recidivism in the US are extremely high.
Second, the article is meant to tell us what some states have been doing to try to alleviate these problems. The main thing that states are doing is to reduce sentences for non-violent drug offenders. However, we are told that this will not be enough because those offenders do not make up a very large percentage of American prisoners.
Finally, the article is meant to suggest what else could be done. Its main suggestion is that states should be more open to releasing people who are in prison for other sorts of offenses. They should experiment with using intermediate solutions that would serve as midway steps between incarceration and freedom. This would, they say, cost less than prison and it would help to ease the transition into freedom for convicts, thus making them less likely to reoffend.