How exactly does the Patriot Act keep "us" "safe" from "terrorists"?

It allows them to intercept suspected terrorist information and plots without violating the 4th Amendment. Well, it still violates the 4th Amendment in my opinion, but it's just that the courts have allowed them to violate it to investigate possible terrorist plots - both domestic and foreign. Now as for who are the terrorists -- well that is questionable, since they basically get to decide that.