Teh-Raw-Rists Ar Bad
Devastating argument-winner and moral blank cheque, Terrorists Are Bad (also, Cohen's Law) is a free-standing justification suitable for almost any occasion.
Most commonly utilised while refusing to apologise for one's agitation for catastrophic foreign policy blunders or in defending the bombing of military targets.
"David Aaronovitch, you stand in the dock charged with committing a Breach of the Peace. The prosecution states that on 13th February 2002 you, David Aaronovitch, did enter the premises of the Islington Bowl-A-Rama, remove your clothing, defecate into your cap, place said cap upon your head and run about screaming.
This allegation is backed up by CCTV footage and fifty seven witnesses speak to your behaviour.
Do you have anything to say in your defence?"
"Why yes, your honour - I may well have stripped naked and shat in my hat, but have you considered the fact that terrorists are bad?
They blow up hospitals and mosques, and are driven by a maniacal urge to kill as many people as possible.
So, I ask you, if terrorists are bad, how could I possibly have shat in my hat? Surely, if terrorists are bad, you must acquit me of all charges."
"By Jove, I believe you are right! Officer, uncuff this man and escort him to the exit."
See also Whatabout?, Kamm's Gimlet, Nobody Could've Predicted, Mea Culpa Sed Tu Quoque Ad Maximum and Will-You-Condemn-A-Thon.