Do you feel that the lack of warrantless wire taps is what enabled the 9/11 hijackers?
I don't think that police enabled speeding by not having radar guns, or that doctors enabled illness by not modern pharmaceuticals.
You can make a good case that moderate uses of both are very helpful to a society, just as overuse can be harmful. As far as the wiretaps go, you can't say for sure we'd be able to prevent 9/11, and I really don't think we should use that as a reasonable goal. I do think we would have made 9/11 less likely. At least it would have given us a fighting chance.