A wall like that could never be built like that here in america. The enviornmental groups and the dems in california are up in arms about Bush signing a bill to finish off 6 miles of a short span of a wall to the california coast. Sierra clubs and dems wouldn't stand for it.
Also in many of the states especially texas the land is owned by private property owners who won't even let the minutemen on their land let alone allow the govt to build a wall on their property.
What we really need is federal enforcement inland by local police. We need to stop the catch and release policy after 14 days. We need to stop the anchor baby policy which is being brought up in congress but harry reid will fillabuster.