@Ditkaless Wonders
I understand your view that deportation of those who are here illegally is desirable from the standpoint of respect for the rule of law. I disagree with your conclusion, but I am sympathetic to the logic of the underlying argument. I do think that you are missing the boat on the impact that doing so would have on the US economy, particularly as it relates to employment. As you point out, the idea of doing it instantly with the push of the button is a straw man that probably isn't altogether helpful to a reasoned discussion of the topic. I withdraw it and will instead focus on the idea of practical en masse deportation, which seems to be the underlying goal of the current Administration.
I think the notion that the vast majority of undocumented/illegal workers do low-skilled work that makes them highly fungible with any currently unemployed person is overly simplistic. As a gross generalization, it might be correct that the average skill level of undocumented workers is slightly lower than the labor force as a whole. Or it might not. I really don't know any way to statistically judge that, since data availability on undocumented workers is understandably in fairly short supply.
I do have an interesting recent anecdote. We are currently remodeling a house and I was talking to our contractor about worker availability, which is a challenge right now in our area. Out of curiosity, I asked him about the day laborers that gather outside the local Home Depot (as they seem to almost everywhere). He said that he can't and doesn't employ them because of the risk of doing so: he could get fined and/or suffer other unpleasant legal consequences. He also said that, in our area, those guys generally ask for and get $15-$25/hour because most of them have significant skills in construction.
That anecdote illustrates two important points, I think. First is that even among the stereotypical "illegal" population, Latino men standing outside Home Depot, there are skills and abilities significantly above simply a strong back and a willingness to work for low wages. The second important point is that there are striking differences in labor market conditions in various locales. I am sure you know the latter, but it is important in this context. Unemployment in my area is low enough and specific skills are in short enough supply that guys outside of the Home Depot can ask for and get double the minimum wage, even while there are counties in my state where unemployment is close to double the national rate.
I think a couple other misconceptions likely underpin some of your analysis of the economic impact of these workers being deported en masse.
Doubtless you are aware of the decline in labor force participation among prime working age people over the last several years. You implicitly referenced it in your discussion of the ready supply of unemployed persons who could easily step in and take over for deportees. What isn't well known or recognized is that the majority of the decline in labor force participation isn't due to long-term inability to find gainful employment (the stereotypical discouraged worker), but rather a slew of other reasons.
Chart for illsutration
Certainly there are too many discouraged workers out there, but they tend to be concentrated in communities that offer little in the way of economic dynamism. By and large, undocumented/illegal workers tend to be concentrated in areas with a high degree of economic dynamism. So there is a spatial mismatch to consider, in addition.
I don't know to what degree this assumption influences your view, but it is worth mentioning that the idea that the long-term unemployed in this country got that way because of unfair competition from illegal workers is mostly wrong. This notion is commonly held in some quarters. I believe it to be wrong, based on both data and anecdotal information/logical inference. One of the favorite arguments of supporters of protectionism in terms of international trade is that the US manufacturing sector is dying. I have seen that argument also applied to illegal immigration.
The problem with this argument is that the US manufacturing sector isn't dying, it is fairly thriving. Real (as in, inflation adjusted) output from the US manufacturing sector is either at or near an all-time high. And yet the US manufacturing sector has shed ~6-8 million jobs since 2000. It turns out that something on the order of 85% of those jobs were lost due to technological change (automation replacing workers). That leaves the remainder that have been lost due to other reasons. Certainly it is possible some of the remaining jobs have been taken by illegal workers competing with domestic workers, but that isn't going to be a large number because enforcement of labor laws on manufacturers is structurally easier (and therefore more effective, presumably) in industries with fixed locations and a steady/permanent workforce than it is in fields like construction and agriculture. Robots, not workers in China nor illegal workers in the US, have taken the vast majority of those manufacturing jobs.
I would also point out that even now, with millions of people who are out of work and have been so a long time, employers find it very difficult to find qualified and suitable people to fill a wide variety of jobs. This is the so-called "skills gap". While lots of people understand that there is a skills gap in science, engineering and technology fields, fewer are aware that there remains a real skills gap in the trades and among skilled manufacturing workers. (Mike Rowe isn't an economist or a politician, which is probably one reason why
his thinking on this topic is so clear) The latter is an area where I am certain undocumented workers are already participating to a significant degree.
So, in conclusion, en masse deportation of illegal immigrant workers is likely to be highly disruptive to industries far beyond construction and agriculture. And because of spatial considerations, the current under supply of workers with specific skill-sets, and a number of other factors, the job openings created are not likely to be easily filled by the ranks of those unemployed or not currently participating in the labor market.