The "I'm for Legal Immigration" Dodge
My response to a common, but vacuous trope often brought up in debates about immigration policy.
Imagine a debate about marijuana legalization. One participant avows that "I'm for legal marijuana. I'm only against the illegal kind." Most people will readily see that he is evading the issue: the whole point under discussion is whether existing laws banning the sale and possession of marijuana should be liberalized, or perhaps abolished entirely.
Along the same lines, imagine a debate over racial segregation circa 1960. One participant says: "I'm for legal integration. But I'm against the illegal kind." Here too, it's obvious that the person who said that is missing the point. The question at issue was whether existing segregation laws should be abolished (or at least severely curtailed). If she wants to argue that segregation laws are fine in some states (those that had them at the time), but wrong in others (those that did not), she needs to provide some explanation for why segregation is right and just in the former locations, but wrong elsewhere.
The same goes for almost every other context where there is a debate about liberalizing laws restricting some activity. Everyone who follows such questions recognizes that "I'm for legal X" is an evasion of the real issue, one that does nothing to advance the discussion.
The big exception is immigration policy. There, we routinely hear variants of "I'm for legal immigration, but against the illegal kind." And many see this is as a serious argument.
In reality, it is no more valid than similar statements in the context of segregation, the War on Drugs, or anything else. The whole point at issue in discussions of immigration policy is whether various types of immigration should be legal. Saying "I'm for legal immigration" does nothing to address that question.
If the idea is that you support currently legal immigration but oppose any that is not currently legal, than you need to explain how and why status quo policy draws the right line—much like the person who supported segregation in some states but not others in the example given above had to explain what the difference between the two types of states is. The "I'm for legal immigration" mantra does nothing to refute arguments to the effect that current immigration restrictions are unjust, cause enormous economic harm, and threaten the liberty of natives as well as would-be immigrants.
If the claim here is that people have a moral duty to obey immigration restrictions until such time as they are properly repealed by Congress, that still isn't a response to claims that some or all of those restrictions should be abolished. Indeed, the greater the obligation we might have to obey even unjust and harmful laws, the greater the moral imperative of repealing such laws as quickly as possible.
Even on its own terms, the duty-to-obey-the-law theory has to confront arguments to the effect that many immigration restrictions are so severely unjust that migrants do not have a duty to obey them. That challenge is especially hard to meet if you, like many Americans, accept the idea that it's perfectly fine to routinely disobey a wide range of less onerous laws, such as speed limits and various petty economic regulations. Regardless, the issue of whether people have a duty to obey a given law is conceptually separate from the issue of whether that law should exist in the first place. Most debates over immigration policy are actually about the latter issue.
Similarly, if your objection to currently illegal immigration is that it undermines respect for the rule of law, then that's a great justification for legalizing it! That would solve the problem far more thoroughly than any crackdown possibly could. If you think that illegal immigration undermines the rule of law in ways that the lawbreaking most of us engage in on a routine basis does not (most adult Americans have violated federal criminal law at some point in their lives), then you must explain what it is that makes immigration law special.
Finally, if you really do support all currently legal immigration, and oppose only the illegal kind, then you should oppose Donald Trump's and some other Republicans' efforts to severely truncate currently legal immigration. If you are indifferent to such plans or actually back them, then you are not for currently legal immigration. You're for massively cutting it, and you should defend that position.
There are plenty of intellectually serious arguments for restricting immigration, including some for cutting it below current levels. I address a wide range of such claims in my recent book Free to Move: Foot Voting, Migration, and Political Freedom. But the "I'm for legal immigration" trope is not a serious contribution to the discussion. The sooner we can retire it, the sooner we can focus on the real issues at stake in debates over immigration policy.