KHAN YUNIS, Gaza Strip — It's blazing hot every day; the electricity comes and goes. And when there's no electricity, there's no water. Nobody has any money, but everyone, it seems, has a weapon. The Israelis left the Gaza Strip last fall. But now they seem to be everywhere at once — on the ground, in the air and even on the other end of the telephone as a voice warning civilians in accented Arabic of impending missile strikes. There's no way out. The borders are closed for months at a time to all but foreign passport holders and those...