The argument against the fence is that it would cost $70 million to build EACH mile of fence?
Bull sh!t.
I didn't look at the CRS report itself, so I am not sure where they came up with the costs, but I am sure it included the costs of acquiring the land, environmental impact reports (can't affect any endangered species!), site preparation, getting the materials and equipment into the location (some places on the Texas border are very hard to reach by vehicle), etc. The costs also includes the maintenance of the fence for the next 25 years. If you don't maintain it, you may as well not build it. You have to figure that into the cost as well.
Some of the sound walls along the highways leading into Detroit are 20 and 30 feet tall, maybe more. They appear to be poured concrete and they go for miles. I doubt they cost $70 million per mile.
The fact is that the argument is packed with straw men on the open border side. Simply stated, what is America worth to us? If it costs $50 billion for that first line of defense, so be it. In fact, no price is too high to save America.
Something else that needs to be considered is the stability of Mexico. If we stop releasing the pressure on Mexico, Mexico will eventually stabilize. After all, there’s a reason we don’t have a massive illegal immigration problem from Canada.