yes, it still is
The threat that nuclear weapons would be used.
No, but it would be nice to see them have nuclear weapons, considering that Pakistan and India are nuclear nations.
Nuclear weapons are a good thing for the United States because they prevent others from using nuclear weapons on the US. In general, the world would probably be a better place without nuclear weapons if it weren't for the fact that they lead to research in all fields of Nuclear Engineering, like Nuclear Power plants and Nuclear Physics. Since nuclear weapons already exist in the world, for the US to get rid of their nuclear weapons would be unwise. Countries that dislike nuclear weapons or even radical terrorist cells and organizations would now have no reason not to launch a nuclear warhead at the US since no retaliation would occur. The strategy of nuclear weapons preventing others from using them against the US is called the Deterrent Strategy.
It would probably be nuclear pandemonium.
No nuclear energy, no nuclear weapons
nobody
Any decision by the UK to go to war, or to launch nuclear weapons, would have to be made by Parliament.
Because there was no true defense against nuclear weapons. Once both sides had nuclear weapons, the only way to "protect" themselves from the other side was to have so many more nuclear weapons that even if their enemies used all of their nuclear weapons, there would still be nuclear weapons to shoot back with. That way, nobody would use nuclear weapons, because they could never actually "win" that way. This thought process was referred to as Mutually Assured Destruction, or MAD.
This is actually a rather complicated situation.On the "yes" side: Japan certainly has the expertise, technology and equipment to construct nuclear weapons. They also have ready access to weapons-grade raw materials.On the "no" side: Japan has a non-nuclear policy (to be clear here: that refers to weapons, not reactors for generating power) and construction of nuclear weapons may be forbidden by their constitution (whether or not small "tactical" nuclear weapons would be forbidden is a question of interpretation). So far as is known, they've never conducted any nuclear weapons testing... and the US would almost certainly know if they had.Probably the best answer is: there's no particular reason to believe that Japan has nuclear weapons at this moment, but there's also no particular reason to believe they couldn't put one or more together on very short notice if they really wanted to.
At this point in time (2012) Iran is believed to have no nuclear weapons capability at all. However this could end at any time (at which point Iran would be nuclear weapons capable).
Because nuclear weapons are the most deadly of all weapons and can kill hundreds of thousands of people at once. Also, people will always get suspicious if a country is secretly making nuclear weapons e.g. Iran and USA. IF one country wants to build nuclear weapons then their neigh ours would want to too
both