Marco Rubio’s candidacy for the presidency was damaged by his membership of the Gang of Eight, the bipartisan group of U.S. senators that promoted amnesty and a path to citizenship for illegal immigrants. In an attempt to repair that damage Rubio now says that the gang’s amnesty plan was a mistake, because both the border and the legal immigration system need to be fixed before we can talk about what? He won’t say what that is because we can’t even discuss it until the other two things are fixed. Though this is offered as a principled reason not to get into the subject it still looks too much like dodging an embarrassment, and in any case when Rubio persistently refuses to rule out a path to citizenship it’s clear enough that that’s what he intends.
But this new Rubio stance of first fixing the border and only then granting amnesty or a path to citizenship is completely incoherent. To
understand why, we need only think about what causes a substantial flow of illegal entrants in the first place. The magnitude of a flow of people crossing the border illegally is determined by the interplay of two factors, and in this sense it is rather like the flow of an electric current. Ohm’s law says that current is indirectly proportional to resistance, and directly proportional to voltage. In other words, the more resistance there is to the current, the less current flows, and the greater the electro-motive force or pressure propelling the current, the more current flows. There are two variables, not one.
Similarly, there are two major variables that determine the flow of illegal entrants across our borders. The more difficult we make it to get in (by building physical barriers, for example) the smaller the flow will be. This is the like the resistance factor in Ohm’s law, but it’s not an absolute: it doesn’t stop illegal entry, but only reduces it to a greater or lesser extent depending on the degree of difficulty that the barrier presents.
The second variable is the motivation of the migrants. The more determined they are to get in, the greater the flow will be. That’s the equivalent of electro-motive force in Ohm’s law. This factor too is not an absolute: it’s only one of two variables that interact to determine the size of the flow. Incentives are the key factor. If potential migrants think their lives will be only moderately improved by getting across the border, they’ll be less motivated than if they think their lives will be changed out of all recognition. A really tough border barrier will stop people whose motivation is weak to moderate, but if the motive force is strong enough that is, if migrants are really determined then there is no wall high enough to stop them.
And that is why Marco Rubio’s current stance on illegal immigration is utterly incoherent. If you increase resistance to illegal entry by building a wall, but then greatly increase motivation to get in by promising the huge reward of citizenship (much more then amnesty) to those who have entered illegally, you will have achieved precisely nothing. The flow is reduced by the one measure, then increased again by the other. It’s as if Rubio were repealing Ohm’s law, and telling us that current only varies with resistance.
Fixing the border is not achieved by building a wall. It is achieved by building a wall and at the same time making it clear that there is not much to be gained by climbing over it. Decreasing the flow requires both raising the resistance and lessening the motive force. A path to citizenship, legalization, lax enforcement of employment laws, non-enforcement of criminal penalties for illegally crossing the border, sanctuary cities, driver’s licenses, in-state tuition, anchor babies, immunity from prosecution‹they all increase the flow by giving more reasons to get over the wall. Proposing to erect a wall while also keeping incentives to cross it in place is self-contradictory nonsense.
John M Ellis is a Professor Emeritus at the University of California, Santa Cruz, and Chairman of the California Association of Scholars