Just to be clear on the historical record, almost all Americans by birth, naturalized Americans and resident aliens of Japanese descent were all rounded up from the west coast (but, oddly, not Hawaii) and interred in quite austere and miserable concentration camps. The US Supreme Court allowed it under the Executive's war powers. There was no consideration given to any evidence of an individual Japanese-American's loyalty or risk of disloyalty. It was enough just to be of Japanese ancestry. In contrast, German-Americans were not rounded up, but were evaluated or monitored based on their perceived individual loyalty or lack thereof.

There was never any evidence of Japanese-American spies or saboteurs operating on the west coast. But they did catch German Americans landed as saboteurs by U-boat on our east coast, and of course there was the large pro-Nazi American Bund organization and even the Nazi-funded "Silver Shirts" operating in America right up until Pearl Harbor. Many young Japanese-Americans, including recruits drawn directly from the camps, served with great distinction fighting in Europe.

Today, most experts see this as a result of war hysteria heavily, very heavily, tinged with racism, and a deeply shameful episode in American history. Decades later, there was an official apology and some reparations, but these were far less than the financial value of the homes, farms, businesses and other property Japanese-Americans lost as a result of internment.