I not aware of anyone who ever said that.
The issue has always been what you have to do to seal, close, control the border and how long do you have to do it. And of course, what about the canadian border with 1000 agents only?
Read bayourod's post #7, if that's not saying the borders can't be sealed than I don't know what is.
As far as the Canadian border: put the military up there too, we're vulnerable from terrorists and illegals entering there as well.