If we're talking about 'reasonable' conservatives, the typical answer is that booking people who commit a crime, and then using the threat of prison time to for

If we're talking about 'reasonable' conservatives, the typical answer is that booking people who commit a crime, and then using the threat of prison time to force them into rehab will ultimately be much better for them and the community than immediately releasing them under the guise that poverty causes addiction and crime and that therefore they are essentially blameless. Some former addicts attest that, when they were addicted, it was only the threat of prison time that could force them into rehab, because at the time they were not fully in control of their own decision making. They say the 'stick' helps motivate them to choose rehab instead, and it ultimately helped them out of a bad situation. Sam Quinones' book, The Least of Us, documents some of this and is well-researched.