[Protagoras]

To answer my own question of you, it is not in your rational self interest to become a thief and a murderer as there are likely negative consequences to those actions.

What you think is in a persons rational self interest is not the same as what he thinks.

Not to mention, "likely" consequences aren't so likely in many cases. And it plays right into what I said in an earlier post, if there is no morality, there are only actions and consequences. It sounds like you agree with that, but perhaps not. And the question remains, is an irrational person capable of doing right or wrong.

What about a quite rational Muslim extremist? What about a NAZI? What about a Bushido Japanese? All quite rational. And all quite evil.

[Durus]

If what one "thinks" is in conflict with reality then their thoughts are not rational. Regardless of ones moral upbringing people are still capable of evil.

You mention "only" actions and consequences. One could easily claim that Christians obey the dictates of G_d not out of a sense of morality but to escape eternal pain in hell. This, if accepted, and I don't, would indicate that there is not a higher morality but simply actions and consequences.

Is an irrational person capable of right and wrong? Of course but likely by mistake.
There is nothing rational about Muslim extremists and there is nothing rational about Nazi's. Bushido, as I understand it, is neither an ideology nor a religion...but regardless I don't know enough about it to determine its rationality.