Kant thought that the domain of the ethical is circumscribed by the question: can some contemplated act be universalized? Is it something everybody should do?  If yes, the act is ethical. If not, not.

‘The west’ is involved in asymmetrical warfare with ‘terrorists’.  The asymmetry does not have to do only with the difference in technology between the two sides.  It also has to do with the fact that both sides continually commit acts which would be catastrophic if universalized. They are asymmetrical also in the sense that their acts are proscribed for everybody except themselves.

Do you believe it is OK, even good, to do to others what should not be done to you?

Congratulations!  You are a conservative!