>If NK attacked and bombed Japan, what would we do? Could I say, "we'd never scurutinize any suspicious person(or agent) because of thier nationality? That's tough to answer.
This is a tough issue in the US as well... It's called "Racial Profiling." Arabs or people with Arabic names often get more closely scrutinized at airports... This doesn't really seem fair, but almost of the people involved in the 9/11 attacks, as well as the 3/11 attack in Spain last year, the attack on the USS Cole ship in 2000, and many other attacks against Americans and allies have been Muslim Arabs. Of course, very few Muslim Arabs actually want to blow up buildings, so it's unfair to treat them all as if they might be murderers, but... It's definitely not an issue with an easy answer.
Personally, were such a thing to happen, I hope you would not harbor resentment toward the NK people. The Koreans are fine people; it's their government that's crazy.
>Not to change the subject, but I'm curious to know whether your nation gives suffrage to whoever live in it but doesn't have the nationality.
If you are referring to the United States, then no; you must be a citizen to have voting rights. Surely Japan doesn't allow such a thing... do they? It would seem quite bizarre to me. Anyway, becoming a legal citizen of the US is a fairly simple process compared to most other countries.
>So they don't have the abilitiy to interrogate any person and put him behind bars?
The Constitution of the US says a lot about this issue. One of its most important parts says that someone can't be arrested unless they are charged with a crime, soon after which they must be allowed a fair trial. If, however, they cannot charge someone for a crime, because of lack of evidence or for any other reason, that person must be let go. So it is illegal to arrest a US citizen and hold them indefinitely.
Where this gets tricky is that this is exactly what we're doing to a lot of terror suspects... Have you heard of the Guantanamo Bay base in Cuba? Many people are being arrested (mostly from overseas, but some from America) and imprisoned there while they are interrogated about their connections to terrorist groups. However, as these people are not US citizens, this is not a violation of the Constitution.
This doesn't sit well with some people, who think that the Constitution should apply to the government's behavior to non-citizens as well. Myself, I don't think that should happen, but I'll admit that I do find the idea of what's going on at Guantanamo Bay a bit unsettling.
By the way, I'm not sure how many of you Japanese folk are posting here, since you're all posting anonymously, but I must say that you all have some pretty solid English skills. Good work.