constructed were in fact replacements for previously existing barriers.

Like everything else with Trump, its all smoke and mirrors. He has no interest or will to pursue anything that does not benefit him or his circle of cronies directly. "Build that wall", is nothing more than a distraction to keep you from concerning yourselves with his real agenda, "Make Trump Great", no matter the cost. He didn't run because he cares about the country, he ran because Seth Meyers and every other comedian and pundit mocked him mercilessly. He spent his whole life believing personal wealth was the ultimate scorecard of a person's merit. He had enormous personal wealth, a highly rated TV show, a former model wife, and he was still seen by most Americans as a complete buffoon. His whole presidency is an attempt to gain some semblance of respect and power. He'll wield any weapon he can to stop them from laughing at him.