Ab-so-damn-lotely!
And why do we get apologist shills on FR who insist that perfectly secure borders are impossible. Of course that's true, but it's not the point. Point is: Arrests of AQ people have stopped attacks, or at least delayed or blunted attacks. A real effort at securing our border will do the same: reduce the number of infiltrators, reduce the number of attacks, and save many American lives.
I'm no Bircher, either. I'm pro legal immigration especially on a selective basis. But the border situation is inexcusable.
Hmmm... must be all those ILLEGAL ALIENS from Mexico!