Having a kill switch for the Net is an unbelievably bad idea.
There are two reasons.
1. If a political actor wanted to kill off a large group of people without the government calling in the army to intervene then it would need a definite window in which to do so. It would do whatever it took to trigger the killswitch. Then it could have its merry way.
If a government wanted to do this there is not much you could do to stop them. That doesn't mean you should extend the possibility to every other political actor!
2. If things are really getting bad for any reason, you already have the power to turn off 99% of the Net by turning off the electricity supply. The hospitals and other important infrastructure already have gas or oil backup generators. That this is an option with a risk of political/economic ramifications should mean it shall not be exercised much which is all to the good.
tldr; Don't do it. You'll get manipulated by people who are smarter and more dangerous than you are.
There are two reasons.
1. If a political actor wanted to kill off a large group of people without the government calling in the army to intervene then it would need a definite window in which to do so. It would do whatever it took to trigger the killswitch. Then it could have its merry way.
If a government wanted to do this there is not much you could do to stop them. That doesn't mean you should extend the possibility to every other political actor!
2. If things are really getting bad for any reason, you already have the power to turn off 99% of the Net by turning off the electricity supply. The hospitals and other important infrastructure already have gas or oil backup generators. That this is an option with a risk of political/economic ramifications should mean it shall not be exercised much which is all to the good.
tldr; Don't do it. You'll get manipulated by people who are smarter and more dangerous than you are.