i think there should be a wall. i just don't agree with the 'blame bush' scapegoat mentality. federal troops have very little legal ground inside this country when it comes to law enforcement issues
Therefore, couple that fact with his available tool, "The Executive Order", the walls and fences could have been already built since 9/11 as well as the actual 2000 border agents promised in recent legislation (2004 I think) that funding was appropriated.
Congress is the second line of defense, and they too, on both sides of the aisle have chosen to do nothing.
The judicial system, the 3rd line of defense does nothing to enforce current law other than catch and release.
So, I have to say, W is the no. 1 scapegoat at this time because he has ultimate authority initially to protect this nation's security.