The right to respond

When a country is attacked does it have the right to respond? Is responding to the aggressor with consequences a moral imperative?
Alternatively should it "turn the other cheek" so as to avoid "escalating " the situation?

Lets look at history.

When Germany invaded Poland the UK issued an ultimate for Germany to withdraw, the didn't and the UK declared the start of WW2.
When Japan bombed Pearl Harbour the US declared war.
Both of these retaliations resulted in millions of deaths, should the UK and USA have "turned the other cheek".

When Osama Bin Laden co ordinated an attack on the USA the USA, Australia,Canada, UK etc invaded Afghanistan to kill Osama. Was that justified?

Hamas attacked Israelis and took hostages, is retaliation justified?

In my opinion in all these examples it was best to retaliate, otherwise aggression will increase and the world would be worse off.

bacci