Simple.

It's not wrong to defend your own life (or another person's) against attack, even if this causes the death of your attacker - and it's legitimate to use a gun or any other weapon that comes to hand in doing so.

Please note, I said "life". It would be wrong to kill an attacker if you did not fear for your own life (or for another person's), but you may still defend yourself as much as necessary to avoid hurt. I cannot imagine how a gun would be an appropriate defence weapon here.

A thief's life is not forfeit because he breaks the law, nor is a mugger's, nor even a rapist's (waits for the reaction!). But his freedom should be.

Killing national leaders who are oppressive has a recent precedent in Saddam Hussein. He was hanged supposedly for just the reason I have advanced for attacking Zimbabwe. Mugabe's death is just as desirable as Saddam's. I would not have him killed because he is a megalomanic, nor because he is a rascist, or because he is anti-British. I would have him killed because he is killing fellow Zimbaweans in order to hold onto illegitimate power, and he is presiding over the ruination of his country and his people. However, I would be satisfied if he were simply removed from power so that aid could reach the people.

Am I mistaken? Am I hippocrytical?