Working on the fairly reasonable - but not definite - assumption that a wall would actually work, one benefit would be that these emotional reactions would subside. But if every politician and movement in America that calls for taking illegal immigration seriously is reflexively denounced as "anti-immigration," never mind racist, then you won't get rid of those sentiments, you'll feed them. In other words, if you don't have a reasonable "anti" immigration movement, you will get an unreasonable one. That's what's happening in parts of Europe.
Opponents rightly say you don't need a wall if you simply enforce the laws we have now. OK. But there's very little reason to believe that moment is just around the corner. They sound like the guys watching Noah load the ark, saying, "All that work will be unnecessary once the rain stops." And, whenever politicians suggest actually doing that, many of the same critics object to that symbolism as well. Indeed, enforcing the laws by placing thousands of armed men - troops, in effect - along the U.S. border isn't a great look, either. And, historically, troops on the border is a bigger provocation than concrete.
Meanwhile, the Republicans, caving to the business lobby, take the lead opposing a better solution: vigorous prosecution of businesses who hire illegals. If either party were serious about enforcing any of those laws, a wall would be unnecessary.
A wall would not in any sense be "unfair" to Mexicans any more than locks on your windows are unfair to people who want to break into your house and sleep on your couch. A wall would simply put Mexico - and the more than 100,000 "other than Mexicans" who cross our southern border - at the same "disadvantage" as would-be immigrants from Nigeria and New Zealand. They'd have to fill out a form and wait in line.
It feels unserious to say this is ultimately all about symbolism, but that's where I come down. I think the economic arguments on both sides are usually unpersuasive. Paying busboys $10 an hour, one probable upshot of a complete halt to illegal immigration, isn't major progress in my book. And it's hard to take liberals seriously when they complain about the costs of a wall - estimates vary from $15 to $30 billion - when they regularly champion other grandiose public works projects. Clearly the cost isn't their real objection.
So here I am torn between two bad symbols. Everyone likes to quote Robert Frost's line that "good fences make good neighbors." But they leave out the opening line from the same poem, "Something there is that doesn't love a wall." That sums up my continental divide.