“Copperheads” or Americans in the North who identified with the rebellion in the South were arrested and jailed. One of the more famous was Clement Laird Vallandigham, who was deported. Other Copperheads were also deported and stripped of citizenship. Some traitors were executed. As many as 13,000 people in the North were rounded up and jailed under martial law. The Union government took action against newspapers that identified with the rebellion, closing some. Those expressing opposition to military conscription in the North were subject to martial law penalties. Under the Confiscation Act of 1861, the private property of those – not only Southerners – accused of treason could be seized.
While all belligerents in World War II took action against enemy aliens and domestic supporters of the enemy, Britain under Churchill was particularly uncompromising in this area.
There had been about 20,000 German nationals in Britain in 1930, but this number grew by about 60,000 after Hitler came to power. At the start of the war these came under scrutiny and surveillance, even though some of them were Jewish refugees from Germany and Austria. All Germans and Austrians over the age of 16 were called before special tribunals and divided into three groups:
• “High security risks,” who were immediately interned. About 600 fell under this category.
• “Doubtful cases,” who were subject to supervision and restrictions on their movements. There were around 6,500 of these.
• “No security risk,” numbering around 64,000, who were not restricted. Most of these were Jewish refugees from Nazi oppression.
Britain had historically made liberal use of internment as an instrument against the enemy, especially during the Boer Wars. The British intensified their operations against potential spies after 1940, arresting Germans, Austrians and Italians in larger numbers.
On May 12, 1940, more than 2,000 male aliens living in British coastal areas were arrested under special orders of the Home Secretary. The Treachery Act passed Parliament that same year and allowed for the prosecution of any alien suspected of espionage or hostile activity, and included provision for execution of foreign spies.
Churchill ordered that all 19,000 Italians in Britain be rounded up, even those who had lived in the UK for decades. Internment camps for these enemy nationals were set up around Britain, including at Huyton near Liverpool and in large camps on the Isle of Man. In addition, over 7,000 suspect aliens were deported, mainly to Canada and Australia. Tragically, in some cases these included non-British Jews, for fears that German spies might infiltrate Britain while among them.
Canada interned 80,000 people during World War I. While the massive internment of Japanese-Americans by the United States during World War II is well known, less well known is the fact that thousands of ethnic Japanese were interned by the Canadian government.
Australia also ran internment camps, holding as many as 7,000 Australians, plus thousands of aliens sent there by Britain.
While their numbers were much smaller than those of the interned Japanese-Americans, hundreds of Italian-Americans were interned by the U.S. during World War II, and other restrictions were applied to Italian-Americans who were not interned.
German-Americans were subject to restrictions during World War I; over 6,000 were arrested and more than 2,000 were interned. Some 11,000 alien Germans were interned in the United States during World War II.
Surprisingly, given the pro-Nazi sentiments found among some American ethnic Germans and the operation in the U.S. of several pro-Nazi organizations in the 1930s, German-Americans were not interned during World War II, though some other countries in the Western Hemisphere did intern domestic ethnic Germans. Small numbers of ethnic Germans were evicted from sensitive coastal areas of the U.S. After Pearl Harbor the U.S. outlawed the pro-Nazi German American Bund.