When you say "just a function of supply and demand". This only applies to perfectly competitive markets where everyone has perfect information. The labor market is a textbook example of information asymmetry.
Your point rings true, but I think you're talking more about more microscopic asymmetries in wages. Certainly in some areas of the country you have a demand for labour that is not satisfied by cross state migration, however the aggregate demand doesn't really change. When you add excess labour to the closed system (The whole of the US labour market) it will inevitably reduce demand as companies looking to fill roles are more easily able to do so.
> When you add excess labour to the closed system (The whole of the US labour market) it will inevitably reduce demand as companies looking to fill roles are more easily able to do so.
An increase in supply will result in an increased supply. But as I've said in another response--adding people to the economy also tends to increase the aggregate demand for labor. It's not a simple function.
>Adding people to the economy also tends to increase the aggregate demand for labor.
I agree, but the contention is the lag between growth in demand and new immigration. More people will consume more and increase aggregate demand, this we agree on. Most new immigrants don't add a lot to domestic consumption especially if they come from a background of relative poverty. So finding that balance is important.
Just to state, I am more for increasing immigration for people with advanced degrees, but when it comes to low skilled immigration I feel that as a nation we owe it to our poorest to look out for their interests as long as wages remain stagnant for their income strata.
We don't know what the impact of low skilled immigrants is on aggregate demand or on wage growth in the short term. Studies done on low-skill immigration are inconclusive. Google, the Mariel boatlift studies for example. Some studies show a decrease in wages, some show an increase, and some show no impact.
Generally this indicates that the effect is too small to overcome statistical noise.
In the long term however, we have good evidence to support that immigration of all kinds is a net benefit to the economy.
> I feel that as a nation we owe it to our poorest to look out for their interests as long as wages remain stagnant for their income strata.
And if immigration is likely beneficial long term, and the short term impact is unknown or at least too small to easily measure, then decreasing immigration isn't necessarily looking out for their interests (or the interests of their children).
Automation will likely play a much bigger role in wage growth over the next decades, but no popular politicians are calling for an ban on self-checkout lines.
>What’s the evidence that it is beneficial in the long term?
This is the consensus view among economists. If you do some searching it's going to be hard to find anyone outside of far right ethno-state proponents who doesn't believe that long term immigration is a net benefit.
"Economic analysis finds little support for the view that inflows of foreign labor have reduced jobs or Americans’ wages. Economic theory predictions and the bulk of academic research confirms that wages are unaffected by immigration over the long-term and that the economic effects of immigration are mostly positive for natives and for the overall economy." [1]
>In the short term it’s very clearly negative when you take into account not just wages but increased pressure on housing and infrastructure.
This is not very clear. If you take it to the extreme, sure there is some amount of immigration could cause enough such a strain on housing supply and infrastructure that it would be a net detriment. We don't know what the number is, and there is no consensus view that we've come anywhere close to reaching it.