This is based on a comment I made here.
A counter-argument raised against such citing is that those walls are much smaller than the Trump proposal. It is true that the US-Mexican border is 3,201km long, while Israel has 1,004km of border barriers (708km on West Bank, 245km on Egypt border and 51km on Gaza border) and the Hungarian border barriers are 523km (175km on Serbian border and 348km on Croatian border)–actually, slightly less if one includes natural barriers.
What is missing in this simple comparison is relative populations. Israel has 1,004 km of border wall with a population of 8.5m, so 8,500 people per km of wall.
Hungary has 523km of border wall with a population of 9.8m, so 18,700 people per km of wall.
The US-Mexico border is 3,201km long and the US has a population of 325.7m, which would be 101,800 people per km of wall.
Given that Americans are also, on average, richer than Israelis and Hungarians, the proposed Mexican border barrier is, in fact, “smaller” with respect to population and GDP than either the Israeli or Hungarian cases.
Another argument sometimes mounted against border barriers or border enforcement is that a significant amount of illegal immigration comes from visa overstayers and other people who have legally entered for one purpose but extend their stay beyond their legal entitlement. While this is true, it is no argument against border barriers, which can (as the Israel and Hungarian cases demonstrate) be very effective in stopping illegal border crossings. That they do not also stop overstaying merely tells us that such barriers are not a complete solution to all illegal immigration.
It is also reasonable to regard the two types of illegal immigration differently simply because the overstayers have at least passed some level of entry scrutiny. Moreover, it is a bit difficult to do things such as various forms of infrastructure when you don’t even know how many folk are in the country. (And the notion that the social infrastructure of being a successful country is infinitely flexible, so can deal with any level of inflow of any type, strikes me as just nuts.)
Incorporating or denigrating
The Australian and Canadian experiences suggest quite strongly that effective efforts against illegal immigration can actually help the pro-immigration cause because it does not make ordinary voters feel they have no say. Making voters feel helpless and ignored is not good for politics in general and the politics of immigration in particular. While de-legitimising considering the downsides from migration helps along the process of spectacularly screwing up migration policy.
Of course, if your main operative concern regarding immigration is to show how righteous you are, then making the “unrighteous” feel helpless and ignored, indeed, rubbing their noses in how much their views (and votes) don’t count, may be much of the attraction in the first place. (The term undocumented migrants is a nicely Orwellian way of saying “and your votes shouldn’t count”, though it is only part of the use of language to promote voter irrelevance on migration matters.)
But that sort of moralising arrogance, and contempt towards fellow citizens, is not helpful; however strong and appealing it may be among “progressive” folk. It helps give support for the very populist politics that they so deride; but even that can also be a good outcome for them, as it “confirms” their contempt for their fellow citizens which has become so much an integral part of contemporary “progressive” politics.
Far from comparative size stopping the successful Israeli and Hungarian border barriers being evidence for a Mexican border wall, the Mexican border wall is (relative to population and GDP) actually as “smaller” proposal than either.
ADDENDA: An unusually sensible piece on The Wall.
An amusing post about the success of physical barriers.
The latest poll is from 2012, but includes previous polls and suggests strong support for enforcing laws against illegal immigration.
[Cross-posted from Thinking Out Aloud.]