Nuclear weapons should not be abolished if you could abolish them.

Nuclear weapons cannot discriminate any less than normal bombs. While nuclear weapons can have a massive blast radius, you can still aim the thing, plus there are ways to minimise the amount of radiation such as air burst, smaller bomb, neutron bomb, ect. On top of that the most effective target to nuke is a missile silo which are typically away from residential areas. Plus those in risk of nuclear fallout only really need to stay in a basement for a couple weeks. With your comment on nuclear weapons damaging the environment, keep in mind nuclear weapons aren't much worse than most other weapons. Conventional explosive leave chemical residue that can take decades to decompose while causing many health effects. For instance, the health effects of napalm can be felt decades after their use. People are still getting sick from napalm used in the vietnam war and japan, while the radiation effects of the two atom bombs is less than what you get from flying in an airplane. Now with your comment on demand for nuclear weapons, it is important to note that even without nuclear weapons you are going to have demand for destructive weapons. Recent advance of thermobaric weapons have even surpassed the destructive capabilities of tiny nuclear devices. There are currently no treaties regulating thermobaric weapons so as soon as nuclear weapons got abolished you are going to have another arms race with no regulation. Now your comment on if you use a nuclear weapon you are going to have more demand for them is true. This is the reason why casual use of nuclear weapons is frowned upon. But the reason for the non-lethal purposes for nuclear is not for casual using them, it is for an alternative to using them like they were in WW2. If you were in a situation where you had to use a nuke, would you rather vaporize a city or emp a country? Now again with your comment on the radiation they produce, it is important to know that emp and missile intercepting produce no radiation at ground level, the radiation the do produce is so fine that they stay in the air until they decompose to harmless levels. And in instances of air burst majority of the radiation also stay in the air til it decomposes, and the radioactive material that does fall down loses majority of their negative effects in two weeks. And your comment on the environmental effects produce by instances of sudden and massive temperature and pressure change, is null and void since you would get the same effect from a power conventional weapon. You also made the comment that fission is not something that happens anywhere on earth, please remember that fission is constantly happening in the earth's core and actually produces about half of the heat there. Of course you probably mean on the earth surface but even there you can have natural nuclear reactors. Now your comment that nuclear exchange will leave no winners is only partially true. Keep in mind majority of nuclear weapons used in an exchange are going to be aimed at the others nuclear missile silos. The concept that nuclear weapons will completely annihilate both parties is false. The reason why MAD or mutually assured destruction worked is that there are still going to be major consequences of a nuclear war, such as universal shunning, a few destroyed cities, and a lot of craters. No party really wants such a large amount of destruction even if they could win the engagement. Now the reason your statement is partially true is that in most wars there are no winners, even if you win doesn't mean you don't take losses. Now if you had a full nuclear weapons exchange, the effects on the earth would depend on how those weapons were used. If they were surface blast then the effects of the radiation can be far and wide. Surface blast also produce significant amounts of nitric oxide, which damage the ozone. If there was a extremely large nukes used on multiple cities then you would have a massive fires that could produce enough soot to cause a small decrease in global temperature. Important to note that the extremely large nukes that are good at causing large fires are considered to be ineffective compared to smaller nukes. A single nuke that is a thousand times stronger than a smaller one, is multitudes weaker than a thousand smaller nukes. Also important to note that the surface burst I previously mentioned are unlikely to be used because they produce smaller explosions than airburst nuclear weapons. The radiation and nitric oxide produce by airburst is minimal and aren't going to produce global effects even if used in large quantities. Now my rebuttal to your counter arguments: In any situation where you are willing to use an nuclear emp, you are in a situation where you are willing to use a nuclear weapon regardless. Also keep in mind that there are situations where multiple weaker emps are not going to get the job done. You are not going to know where every enemy is thus you can't hit every enemy with weaker emps, on top of that there are military defenses that are still operational if you don't emp the entire country. Also remember that there are enemy bases in cities, so in order for you to emp with non-nuclear emps you are still going to emp every civilian city. Now you have a misconception about high altitude emps. While there is radiation produce, it still decomposes fairly quickly. And the radiation swept into the Van Allen Belts has zero effect. Keep in mind that these belts get constantly bombarded by something that make our strongest nukes look like firecrackers. The solar wind is constantly producing highly charged particles in this belt, and on top of that solar storms can turn the entire belt into a speedway of dangerous high velocity particles. If you think all of the worlds nuclear weapons shot into this belt would even produce a noticeable effect compared to what happens there regularly, then you greatly disappointed. In response to your response to airburst nuclear weapons. Radiation produce by airburst nuclear weapon becomes negligibly in within a couple of weeks. By future bystanders I hope you mean within days of the nuke being drop because other wise radiation wouldn't effect the people a few months latter. Also important to know that environmental damage produce by a small nuclear weapon would be less than a equally powerful explosion cause by a thermobaric weapon. This is due to the effects of the chemicals in thermobaric weapons can have lasting effects decades later. Also a large thermobaric weapon would create massive fire despite how small or large it is, so your actually more like to have a thermobaric winter than nuclear winter. Now your complaint about nuclear weapons being used to take out ballistic missiles is unfounded. Keep in mind that interception of a ballistic missile is going to happen in space. When used that high they don't even produce an emp effect on the ground let alone and radiation. Your comment on the fact that nuclear weapons are not going to produce good results when used to destroy said asteroid, is correct. I am sorry for not elaborating on uses of nuclear weapons on asteroid since they are very useful for deflection of an asteroid. Important to note that nuclear weapons produce the greatest force of all mankinds weapons. This great force is very useful for deflecting giant objects in space. Several properly positioned nukes calculated to detonated in such a way to deflect a dangerous asteroid, is one of the best hopes we have to prevent such a disaster. Now your comment on the use of gravitational tractor to deflect an asteroid is one I am aware of. Only problem with gravitational tractors is that they require knowledge of said asteroid years or even decades before it hits. If you were to realize it lets say a single year before it hit, you would need nuclear weapons to deflected it. In the end, nuclear weapons have a purpose on this earth.