Simple solution --- Profile, Profile, Profile --- then Profile some more. Detection of potential terrorists isn't all that difficult, everyone knows that except PC liberals ....
The response to the terror threat is easy. Make sure the world knows that that any attack on the United States will be followed by a string of C-5 transport planes bombing Mecca with pig guts. That would show them that the one they pray to is not able to protect them or Allah is punishing them for their actions. You have to react to their barbaric ways with the same actions.
If we profiled, there wouldn't be a Kenyan-born socialist Muslim with Indonesian citizenship usurping the Oval Office.