Hi clo,
The US may not need a wall. But many countries have them and they do something.
Sometimes a wall helps to keep people out who you don't want in. Or to funnel people towards legal crossing points.
I happen to agree that illegal immigration supports US agriculture and other industries. There's a massive net benefit to the country.
On the other hand, legal immigration (eg through a summer work programme) would mean field workers may be less subject to abusive treatment and exploitative wage levels.
The ease of illegal passage across the border results in everyone being complicit in this sort of abuse and exploitation from customs agents to folks purchasing cheap groceries to people in Washington who like the way things are.
So there's a cost of permissiveness. And a wall might reduce that cost, while increasing the cost of produce. A cost see-saw.
For me, it is non-obvious that a wall is intrinsically a good or a bad idea. It kinda depends on what the border threat is. If there were ISIS people on the other side, you'd want a big wall. Luckily for you, it's Mexico down there.
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