Donald Trump and his supporters are absolutely right about one thing when it comes to immigration.
Hold on. I'm going somewhere with this.
It is correct to say that in the United States, and to an even greater extent in Europe, existing laws on immigration are poorly enforced. What they don't understand, though, is that immigration laws have never been enforced strictly, here or elsewhere. It is today and always has been a matter of political expediency to write strict immigration laws and a matter of economic necessity to enforce them with great laxity.
During the first great American hysteria over immigration in the mid-19th Century – the target of opportunity was the Irish, although over the remainder of the century it evolved to Italians, Poles, Slavs, and all nationalities of Eastern European Jews – restrictive immigration laws were passed not infrequently in Congress. And anti-immigration elites (and labor leaders like Samuel Gompers, who feared the dilution of wages) were regularly incensed to see how poorly those laws were enforced. Weak enforcement was, and is, no accident. During the Industrial Revolution, massive amounts of raw physical labor were needed to mine the coal, pour the steel, work the powerhouses, and many other varieties of hard, physically demanding, often dehumanizing work. Since few Americans could be found willing to work themselves to death for wages that ranged from mediocre to scandalous, the captains of industry of the day understood that they needed another source of labor. Eastern Europeans in particular – not a small of stature people by nature – were ideal candidates. And that's why I live in the United States right now, because sometime around 1910 a guy who looks kinda like me was willing to do literally any job for a chance to live here.
The country admitted millions of immigrants who should have been, by the strict letter of the laws, sent back to Europe. But big business has a tendency to get what it wants in this country, and they wanted bodies. Waving those bodies through the gates without too much regard for immigration laws first made our economy great, then made our society great.
Things are no different today excepting the direction on the map from which the immigrants are arriving. Business needs low cost labor for manual and other unskilled work. Political populism demands strict immigration laws to keep the nativist and xenophobic tendencies in the electorate satisfied. Everybody with power gets what they want – politicians get votes, industry gets labor. In a rare example of wants coinciding, the immigrants get what they want as well. As best anyone who has studied the matter now or historically can determine, what they want is little more than a chance to work like dogs for very little money in return for living here.
So, Trump is not wrong when he says immigration laws are enforced haphazardly. What he is too thick or too politically savvy to mention, though, is that people like Donald Trump are the exact reason that this situation exists. Capital wants labor, and American teenagers are not going to pick fruit in 85 degree heat for 14 hours per day with little complaint. If immigration laws were enforced at the level of the employer – imposing severe penalties for any workplace found employing undocumented immigrants – the problem would disappear. Of course that option is not on the table, because everyone in a position to affect these matters understands how crucial that low-wage labor is to our economy. Those guys stand in the Home Depot parking lot every morning at sunrise because someone is going to give them money in exchange for work, not because they enjoy the view.
The incentives are today what they have always been: win votes with rhetoric and laws, keep the cheap labor coming – and the money flowing – with indifferent enforcement. If our economic oligarchs didn't want and need immigrant labor, the wall would long since have been built.