Supposing the leader of your country did something bad. You happen to hold that person’s life in your hands. How badly would the leader have to act before you would consider intentionally ending that person’s life?
Assume no negative consequences for you, other than you knowing you intentionally ended a life. (For example, you are a surgeon operating on the leader and can intentionally do a substandard job, but the death looks completely accidental)
If it helps, you can imagine a ruthless murdering despot or someone quite insane is the leader in question.
Knowingly and unnecessarily killing innocent people would be more than enough for me. I’d be much more likely to kill a leader ( any leader, not just mine ) than some random person, simply because I can’t rely on the law punishing or even restraining him. Also, a leader is much more likely to do death-worthy things that I can be sure can be laid at his door. Before I killed someone, I’d want hard evidence that he did the deed I’m killing him for.
If I was a surgeon I could never do an intentionally substandard job. You have a professional responsibility that in my opinion you cannot mess with. That means you give the same level of treatment to a serial killer/serial rapist who is on your operating table as you do someone who runs a charitable organization that feeds starving kids in Africa.
I think the example in the OP is materially different enough from the general premise to point out my feelings in that regard. The medical profession has to hold itself to this standard.
So long as he held office legitimately, no. I’m a strong believer in the rule of law, and believe there is virtually no potential crisis (barring, say, the leader intentionally starting a nuclear war) that justifies bringing down democracy, because once you break that, you can’t put it back together again. Not without the deaths of thousands and tens of thousands.
However, if my leader cancelled elections I’d kill him in a second.
This link explains a lower level variation of what you are asking about:
It also happened in the First World War (no cites) and my uncle told me of one spectacular example in Burma - it involded a jeep with a folde down windscreen and a rope across the road. I had the impression that he knew of more examples.
In your case I would make an unlikely surgeon, but if I considered someone dangerous and I had the opportunity, then I would consider myself ethically obliged to intercede to prevent him killing other people.