Singapore has much lower crime stats than Norway and the USA [1,2]. Let's take a look at how Singapore treats its prisoners.
The punishment for even minor crimes (like graffiti) includes caning[3]. They stick you in a prison cell for months, and on some random morning, they will wake you up and give you the sentenced number of hard beatings to your backside. The beating is done by someone with specialized training to inflict maximum pain (while remaining safe). So for months, every day you are scared, never sleeping soundly, as you don't know if this will be the night of your beating.
-Would the graffiti rate in the USA go up or down if the USA imposed the same penalties as Singapore?
-Would reducing recidivism rates by 20-50%, as the article claims possible, really be enough to lower crime in the USA to a OECD average level [4]?
-Norway and Singapore each have ~5M people. Singapore has 130 rapes a year, Norway has 1,000. How do you justify leaving the Norway justice system in place to the additional 800 rape victims in Norway, when a better system for reducing crime has been invented?[5]
Maybe the US is stuck in middle-no-mans land that leads to bad outcomes. To address this, they could either make prisons into hotels/universities (Norway) or impose stricter penalties (Singapore). But if someone did something terrible to one of my family members, I know which system I'd prefer.
[1] http://www.nationmaster.com/country-info/compare/Norway/Sing...
[2] http://www.nationmaster.com/country-info/compare/Singapore/U...
[3] https://en.wikipedia.org/wiki/Caning_in_Singapore
[4] https://en.wikipedia.org/wiki/List_of_countries_by_intention...
[5] Of course, it's never fully accurate to measure systems by comparing numbers across different cultures/measurement systems. The main point remains though.