I think this is correct: the availability or lack of manpower isn’t a Constitutional issue. But reflecting on the possibility and ramifications of ubiquitous surveillance is a genuine threat to privacy unimagined by past editors of the Constitution, and it is high time that it was addressed. The question is, how?
Perhaps we need to accept that any governmental surveillance, physical or otherwise, must be warranted. If current warranting is genuinely onerous for routine stakeouts then perhaps that process should be made easier, although with the Patriot Act’s retroactive warrant applications that’s hard to imagine.