"Sealing the border" is flat impossible, much less 24/7 surveillance of the border (by air or otherwise) which is also essentially impossible. With all due respect to Mr. Smyth, does he have any clue what the FOV is for a typical UAV sensor?

No amount of forces we could ever hope to deploy along the border will prevent infiltration. At best the tide can be stemmed from time-to-time, while a real solution to the problem is implemented. And any such solution requires, in my view, the realization that Pakistan and Afghanistan cannot be treated seperately.