RALEIGH — Let’s get some things straight about the idea of raising the cap on the percentage of students at the University of North Carolina who hail from other states. Currently set at 18 percent, the cap has been debated for weeks now by university officials, students, parents, state lawmakers, and others. Unfortunately, this debate hasn’t gotten progressively better. It’s gotten progressively sillier.

I’m against raising the cap, but let me first set aside some of the flimsier arguments advanced by other critics of the proposal, which is reportedly set to be considered by the UNC Board of Governors later this week. First, advocates of raising the cap say that it would increase the quality of incoming classes of students, particularly at UNC-Chapel Hill and perhaps a couple of other schools. Critics deny this, stating that plenty of highly qualified in-state students are turned away now and so a higher cap wouldn’t necessarily improve the academic standing of the institution.

Sorry, but simple logic suggests that the UNC folks are right on this one. By definition, an artificial limit on enrollment based on geography must, in a competitive pool, result in a diminution of the rigor of the resulting class. Perhaps the effects are slight, perhaps scarcely measurable, but they are real. (Of course, the same analysis also applies to other artificial limits or quotas on enrollment, such as racial ones, but if you expect consistency from university officials you will wait a long time.)

Second, some critics of raising the cap resort to a sort of rhetoric snort, something like, “It’s the University of North Carolina, isn’t it? That means it’s for North Carolinians. You just send them Yankees packing!” This isn’t a good or sufficient reason to oppose the proposal. Its advocates obviously believe there to be greater benefits to the state than costs, so just pointing on the costs and fuming about them falls short of a serious challenge.

So let’s talk about those benefits for a moment. One offered by advocates is “diversity.” OK, I’ll grant that running into a fellow student from another part of the country, or another country, can be an enriching and edifying experience. But if nearly one of five students on campus is already from elsewhere, that means there is already a high likelihood of such interactions occurring now. Scooting the cap up a bit isn’t going to make much of a difference, particularly if the resulting influx of out-of-state students is disproportionately concentrated in academic fields where they are already well-represented (which seems likelier than a random distribution).

More importantly, for every nanosecond spent worrying about this tangential issue — “you make your hair differently and you dress differently,” explained one out-of-state student about his peers’ intellectual contributions — UNC and the rest of us are missing an opportunity to worry about the core issues facing the university’s educational experience: the lack of rigor, lack of common curriculum, grade inflation, political bias, classes taught by barely intelligible graduate students or foreign-speaking instructors, and other factors afflicting the classroom on a daily basis.

Another argument is that by bringing more students into the state, North Carolina could create a “brain gain” of graduates willing to stay in the state, start businesses, enliven our communities, and so on. Again, this already happens now, so the argument must be that it would happen more often without the 18 percent cap. I just don’t buy it. Only a portion of the small increment of additional students would do this, and the economic benefits are uncertain (not all out-of-state students are bursting with patentable new pharmaceutical formulas or loads of Mommy and Daddy’s cash to blow through). Unlike the case of academic qualifications, there’s no reason to believe that educating an out-of-stater instead of an in-stater will result in more economic growth and development in the state, especially since a smart North Carolinian seems more likely than a smart non-North Carolinian to want to live in North Carolina.

A related notion is that UNC would improve its fundraising potential by including more (presumably wealthy) out-of-staters. This from one of the most generously funded public university systems in the United States. Please pardon me while I gag.

Still another argument against the cap comes from a fiscally conservative place, believe it or not: that out-of-state students finance virtually all of the cost of their education, unlike in-staters, so taxpayers would save money if the cap were raised. Here’s a case of bad accounting, I’m afraid. Sure, visiting students pay a much higher tuition, but it still falls far short of paying the operating and capital costs of a university education. Remember that $3.1 billion bond issue back in 2000? That was supposed to accommodate an expected surge in enrollment from North Carolina students ready and able to attend UNC schools. Either the projection of need then was too high — gosh, it’s hard to disbelieve any part of that scrupulously honest pitch, I know — or a higher cap would simply swap out-of-state students for in-state students who would otherwise have been accommodated in the new classrooms and facilities.

That would actually shift more of the cost to North Carolina taxpayers, who are directly financing the bond construction’s price tag through the General Fund budget of the state rather than through the UNC allocation (including tuition). The reason is that some of them have children who either wouldn’t be accommodated at UNC or would have to be with still more building and borrowing.

While we’re on the subject of crowding out, the latest iteration of the cap-raising rationale suggests that there need not be a crowding-out. In fact, the cap doesn’t even have to change on a percentage basis. Instead, UNC officials say, campuses could be allowed to offset additional numbers of out-of-state students by attracting more in-state students so that the proportion remains the same.

Uh, so that means we’ll need more professors, more supplies, more classrooms, and more facilities, right? Can you guess who would pay for that? And wouldn’t a global increase in students admitted result in at least a slight lowering of admissions standards?

The real reason that officials want to raise the cap, I’m afraid, is that they care about how UNC-Chapel Hill ranks in the U.S. News rankings each year. That is a completely worthless piece of information to North Carolinians (ask me and I’ll tell you how) but a college administrator may consider it to be worth something to his or her career. If so, I’d urge that administrator to pick out one of the couple dozen universities outside North Carolina that scores higher on the U.S. News survey. And then go there. You’re occupying a post that would better be filled by a North Carolinian.

Hood is president of the John Locke Foundation and publisher of Carolina Journal.