As you can see here, the wall is actually non affective at stopping the crossing, but the enforcement of the border is. A fence would have been just as effective if the enforcement is in place to stop the onslaught.
Then there is the draw on the inside that also needs addressed... These people are incentivised to come here or else they wouldn't come.
That isn't the american border. That's obviously somewhere in Africa, and no one is watching that wall.
No one is proposing to build the wall and then walk away leaving it ungaurded. Yet, all the criticism of the wall rely on exactly that. That's how we know they are disengenuous. Even if the wall doesn't work, what's the harm in building it? $20 billion over 8 years is nothing compared to total government spending. In 8 years the federal government will spend about $32 trlllion dollars.
Build the ******* wall.