Botched SWAT raids are one thing, but I think that genocide in the US is a wee bit far-fetched.
That depends on your definition of genocide. Private prisons are a quickly growing industry. When lots of prisoners starts to be seen as an asset instead of a burden to society, people will be looking for more ways get them, instead of ways to reduce them. This will mean stricter sentencing, more felonies, and little incentive to reduce the problem.
When in prisons people are housed in a place where the majority have hepatitis, many have HIV, and a large percent other pathogens and anyone entering is more likely to leave with one or more than not...
Combine the two, is that not a subtle genocide.
What about when having an arm is illegal or subjects you to laws that could cause you to enter that enviroment?
Genocides don't always happen obviously. In fact even in Nazi Germany most were simply worked to death, not killed outright until near the end of the war. What if thier crime was not so easily identifiable like being Jewish. Many others suffered the same fate as "political prisoners". It is easy to see it was wrong when it included cultural or racial lines, but if you take that out of the equation it would be much harder to see it for what it was. What if all had been charged with a crime, and were not of a specific race or culture? What if they just all believed in a different form of government, or thought it was okay to have arms, or lived a certain lifestyle?
Many others were killed in the same way, but we focus on the Jews because that is the easiest persecuted group to show the policies of the Nazi were evil. Otherwise you would have to judge it on an individual basis. Because working criminal prisoners hard, and being low on supplies like food in war times for them would otherwise not have been such an obvious crime. Executing prisoners for treason or other crimes, instead of for being Jews would not have been so obviously wrong for outsiders to judge. Had they never been conquered many would never have known, and it could have been covered up, just a rumor to fade away by some conspiracy nuts. In fact in Western Germany it was considered just that at the time, some conspiracy theory exagerating events.
Most Germans, most German soldiers, and even many of the Nazis were unaware of the nature of the camps or what went on there. Just like you don't even know what goes on at a federal super max facility in this country unless the media is given a tour. Outside of the Gestapo, and the SS the actual details were not widespread. The only publicized camps were very lush detention facilities, the name of the most famous of such escapes me, but it was more of a resort for criminals. Many Germans never knew more than just general persecution was going on.
Stalin killed many more, yet it was not done to a specific persecuted group in a country that would be overthrown and therefore its secrets reveled for others to judge and punish. Only the sheer volumes of people killed in fact even bring attention to it. If he had just killed several million less it might not even have been noticed. He used secret police, most victims were guilty of a crime, even if it was a BS crime, it was a legitimate crime against the soviet legislation. So most vanished without notice or publicity, and they were after all criminals so it deserved little attention. They didn't storm down the streets rounding people up causing them to fight back or unify, they just plucked them out of society in the middle of the night with Homeland Securi..., erm I mean the Main Directorate of State Security.
http://en.wikipedia.org/wiki/Main_Directorate_for_State_Security_(USSR) (you can look up many other references of them)
Had it not been done on such a massive scale it would have likely never have been recorded for history.