The darkest manifestation of American exceptionalism may be its prison system.
The United States has the highest incarceration rate in the world: It has only 5% of the world's population, but one-quarter of its prisoners. U.S. prisons are dangerously overcrowded, house 10 times as many mentally ill individuals as state hospitals, keep people locked up for unfathomably long periods of time, are plagued by inmate abuse and hold a far greater percentage of the country's black population than South Africa did under apartheid. Nearly two-thirds of the inmates released every year return to prison; crippling discrimination in employment and housing encumbers the ones who manage to function. This is all to say that if you are convicted of an imprisonable crime in the U.S., you generally get shown little mercy.
After decades of bipartisan consensus on criminal justice policy, there are some signs that the federal government thinks that the highly punitive system of mass incarceration seems to have gotten out of hand, and some states are making gestures toward making prisons less crowded. But in order to understand how best to fix these problems, one must look beyond policy tweaks and consider the underlying moral philosophy that explains why a society sends people to prison in the manner that they do. In the U.S., that philosophy is one of inflicting punishment and pain.
In Nordic countries like Sweden, which have far lower incarceration and crime rates, prison is about rehabilitation. And it works far more effectively.