Of course we can build a wall, and it is possible and necessary.
Not much logic in “saving” by not building a wall, but he “...would increase manpower on the border...”
How much would that cost Americans? Less manpower, and an impenetrable wall, in the end, is more cost effective. No illegals running, cutting, and digging under our “fence” (thus eliminating a drain on our state and federal tax dollars and resources), and a more effective means in protecting our borders, and sovereignty.
What a picture of weakness that would project to our enemies.
Why don't you research that cost thing?