As long as McCain has no interest in securing our borders, he is enabling anyone who is interested in getting here and launching an attack of some kind. For that matter, why attack when you can just come across the border and take over peacefully? Talk to me about national security when McCain thinks it is a good idea to build a wall.
Remember, the men who perpetrated 9/11 had entered into this country in the 'legal' way, with visas, etc. No one kept up with them, and some were allowed to slip through the cracks and not be sent back if their visas had expired, but the point is, they didn't sneak over the border, so the border/amnesty issue is a canard when it comes to the real National Security issue.