Building a wall to keep out illegal immigrants is not a novel plan. About 670 miles of fencing on the U.S.-Mexico border was completed in accordance with the Bush administration's Secure Fence Act of 2006. That alone cost about $2.4 billion, for roughly one-third of the entire border and, according to migration experts, some of the easier and less costly areas to fence.
The Secure Fence Act called for 700 miles of fencing, with a double layer throughout, but much of the barrier isn't reinforced this way. Even before the fence reached its first stage of completion, some argued it was not being constructed properly.
"It's a lot more expensive than we expected when we started, and it was much more difficult," said Ronald Vitiello, deputy chief of border patrol for the U.S. Customs and Border Protection, at a Senate Committee hearing in May.
Texas Rep. Michael McCaul, chairman of the House Committee on Homeland Security, said in a January 2015 statement to right-leaning publication Daily Caller (founded by Fox News commentator Tucker Carlson and former Dick Cheney advisor Neil Patel) that "In our conversations with outside groups, experts and stakeholders, we learned that it would be an inefficient use of taxpayer money to complete the fence. … We are using that money to utilize other technology to create a secure border."
Now it's become a presidential election cycle issue, courtesy of Donald Trump's bold words.
"I would build a great wall, and nobody builds walls better than me, believe me, and I'll build them very inexpensively. I will build a great, great wall on our southern border. And I will have Mexico pay for that wall. Mark my words," Trump said in his presidential announcement speech.