In my opinion we are already in the first steps of WWIII. Nipping it in the bud is our only option.
Our attacking them would probably bring their violence right to our door.
Afraid that's inevitable now what with the jihadist attitude and our open borders. Even if we let Hamas et al destroy Israel, they'd simply make us the next target. Only chance we have is to strike fast and hard now. And it may already be too late for that, but at least it is a chance.
Note: “Even if we let Hamas et al destroy Israel...” was a hypothetical. God simply will not allow Israel to be destroyed. Hurt? Yes, as we see. Destroyed? Nope.