"they're" doing it so we have to as well.
So if the murder innocent civilians we should do that as well? If they shoot down random aeroplanes so should we? We absolutely don't have to just because they do it. We should be better than that.
I repeat, all the evidence is that torture is completely ineffective. If we want to stop terrorism torturing suspects is just plain stupid, as well as being wicked.
they are going to do what they are going to do
Torture someone innocent (as will happen) and you risk radicalising them, their family and friends. Indeed, torture someone guilty and you risk radicalising their family and friends. You also risk turning people against you who may otherwise be inclined to pass on good quality information. And, of course, you are handing the terrorists an argument to use for recruiting people and giving them an easy justification for their own use of torture.
best watch a few episodes of 'Homeland'
Homeland and similar productions often suggest torture is effective. It isn't. Every single study ever carried out shows that the intelligence gained from torture is very poor quality. Most of it is downright wrong.
I have to support our security services
I support our security services but that doesn't mean I would agree with them doing things that are wrong and counter productive. Thankfully, unlike the CIA our security services do not seem to engage in torture. They do not appear to agree with your views on the subject.