Executive Order 9066 was signed on February 19, 1942, approximately two months after the Japanese bombed Pearl Harbor and the United States entered World War II. The order provided that citizens could be banned from a hue swath of land on the west coast of the United States, and that citizens removed from their homes on the coasts could be interned in camps. If you look at a map, you will see that the west coast of the United States was the coast exposed to Japan, but certainly not to the other nations who fought with Japan, for example, Germany or Italy. So, one might reasonably question why the east coast of the United States was not subject to the same action, being at least as vulnerable to our European enemies.
While the United States government did round up some Italian-Americans and some German-Americans, most of the people who were rounded up and placed in camps were Americans of Japanese descent. Why? Some people felt (and feel) that because the Japanese had attacked United States territory already, they represented a greater threat to us. But the Japanese were a different race, and many people feel that the property seizures and internment were motivated by prejudice.
The lives of the Japanese people who were interned were ruined. They lost homes, land, personal property, and their sense of community and security. They were law-abiding citizens who voted and paid taxes. Two attempts were made to challenge the government's actions in court, but in both cases, the court ruled for the government. It was not until many years later that the government took steps to compensate these people (or their descendants) for the damage that had been done, in 1968.
I would like to think that the effect this had on our country was that we learned to not make military decisions motivated by racism or any other kind of "ism," but I am not completely convinced that we have learned this lesson because I am sure that many innocent people of Islamic and Arabic origin have suffered since 9/11.
Nine thousand and nine Japanese-Americans were interned in the camps during the Second World War. While few Italian-Americans or German-Americans were interned, nearly all were suspected of espionage or were relatives of important members of the Italian or German armed forces or governments. Those actually arrested as spies went to prison.
The Japanese-Americans, on the other hand, were rounded up on the West Coast and sent to camps. Life was not easy at all, but they did not do slave labor nor were they treated as prisoners in camps in German-occupied Europe or Japanese-occupied Asia. The problem, of course, was that Americans originally from Japan or their children were not "white," and therefore the underlying prejudices of some people surfaced. In addition there were Japanese-American spies, at least a few dozen, although probably not the hundreds the government feared. Pearl Harbor facilities had been mapped out by Japanese spies. The governors of the Western states were the ones who pressured President Roosevelt about this decision, but after the apparent perfidy of the Japanese government people in the US were not disposed to take the chance of allowing Japanese agents free run of the West coast.
As far as the effect on America at large, I doubt there was much. Most people weren't too concerned with it. It was only long after the War that people in America were embarrassed by the situation, and reparations made.