General Discussion

In fact, that's one argument that Holocaust deniers make. It couldn't have happened. The logistics would be impossible.

If countries won't accept deportees, they would just languish in detention camps. Lack of food, medicine, and sanitation would eliminate some if them.

So, because the government does not have the location of all 12 million, that means that "only" 5 million would be rounded up? Well that's ok then, huh? Long as it isn't 12 million?

Rounding up just a few hundred would have a terrorizing effect. One reason for having enemies to target in a fascist regime is to unite people in a common cause. It consolidates power.

The US managed to detain 120,000 Japanese American citizens and immigrants from just a few states in WWII in a short time period. They were taken first to assembly centers like football fields, then placed in quickly built and fortified detention centers.

11,000 German nationals in the US were detained during WWII. 1881 Italians were detained.

https://en.wikipedia.org/wiki/The_Holocaust

Mass roundups don't happen overnight. The can go on for years. Start with known undocumented people. There are ways to track down many of them. Citizens and legal immigrants often get caught up in such roundups and might or might not be released.

There is no shortage of racists and bigots willing to provide information in communities across the country. There are vigilantes willing to "deal with" them in their own way. Once you have targeted them, it becomes open season on hunting them down.

Put them in already vacant facilities until long term detention places are established. Start proceedings to deport them. If places won't take them, just let them rot in camps. Insufficient food, medicine, and sanitation take a toll. Diseases spread. People die. Lose enough and you have room to add new captures without expanding the camps. Worked for the Nazis.

Some statistics on deaths caused by Nazi war crimes.

https://www.statista.com/statistics/1071011/holocaust-nazi-persecution-victims-wwii/