–Tariffs are not paid for by foreign importers of trade goods. They are paid for by the domestic consumers who purchase those goods from foreign importers.Tariffs do not mean that Mexico is paying for the wall.
–Net Latin and South American immigration to the United States has been basically 0 for many years. This means that about as many people who enter the country from Latin and South America leave the US every year. We do not have a border immigration crisis – at least not one being caused by immigrants.
–Most people in the United States illegally have overstayed their visas. In other words, they entered the US legally but did not leave when they were supposed to. They did not sneak across the US-Mexico border.
–The 9/11 highjackers entered the United States legally. Timothy McVeigh was an American, as were his co-conspirators. Neither would have been slowed down by a wall. Nor would have Eric Rudolph or Ramzi Yousef, the first bomber of the World Trade Center.
–Most of the increase in US immigration in the last 20 years (and there has been a LOT of immigration to the US in the last 20 years) has been by Chinese and Indian people, large numbers of whom are higher-skilled workers.
–Building the wall will require the mass taking of private land, cutting off private citizens from their property. Conservatives used to think that government taking land from private citizens was a bad thing.
–Building the wall would radically transform migration routes for animals across the desert Southwest. It will be an environmental disaster of epic proportions.
–Building the wall will require expropriating Mexican land on the other side of the Rio Grande river (an act of war), or will require cutting Americans off from access to the Rio Grande’s water in a part of the United States where water is fantastically valuable.
Politics matters, of course. So does all this.