Can betrayal be justified?

betrayal would possibly be justified under whichever set of morals the person doing the betrayal was acting in accordance with.. or whichever set of morals that particular society, in which the betrayal was taking place, identifies with most strongly. So if a majority of that society saw the betrayal as something acting against its set of morals then it couldn't be justified, whereas in a different society where the act was seen as in line with that societies morals then it could be seen as justifiable to that particular society. Justification is pretty relative to the society/individual.. but who am i to even answer this question? we all observe the world in different ways

I think the generals who betrayed Hitler were thoroughly justified, but Hitler and his followers did not think so. krc950 is right. He is supported by the principles of moral and cultural relativism.

In the event that destruction of all which you ever knew was imminent.
In the further event that no time can remain any other way.
Then you can betray any form of construct devised by man to protect what is yours to save.

There are no doubt other logical avenues, I dislike being tied to the logic of man, but here this is my answer.