In a comment a few days ago in response to my misgivings about a national online database of classes, someone raised the question of why we still have a regional, as opposed to national, accreditation system.
The short answer is, I have absolutely no idea. My best guess is inertia; regional accreditors emerged long ago, and gradually accrued a certain legitimacy. Now, certain regional accreditors are simply accepted as 'legitimate' – North Central, Middle States, NEASC, SACS, etc. The national accreditors that currently exist are generally held in much lower esteem throughout most of higher ed, to the extent that they get any respect at all.
(There are also plenty of well-respected accreditors within specific disciplines, like engineering or nursing. Here I'm referring to organizations that accredit entire institutions.)
Until the rise of online courses, the fact of regional separation didn't matter all that much. Credits can transfer between regions without issue, so it's not a matter of compatibility. (We've had students transfer here with credits from all around the country, and we've accepted them without hesitation.) Since each agency has its turf all to itself, there hasn't been much issue of a race to the bottom. If anything, there could be a sort of watered-down “laboratories of democracy” argument that having different agencies across the country can allow for simultaneous experiments. For example, North Central allows AQIP as an alternative to the decennial monster visit; to my knowledge, the others don't, at least for now. (I may be wrong about the Western states; Western readers are invited to correct me on that.)
Some for-profits have already run into some weird accreditation issues as they've gone national. The University of Phoenix, for example, is accredited by North Central, even though it has campuses and students in states that would normally be covered by, say, Middle States. I've heard of occasional hiccups in transfer depending on how local policies are phrased. For example, a college in Pennsylvania might balk at taking credits from an in-state U of Phoenix campus, since it only accepts in-state credits with Middle States accreditation. But this is an easy glitch to fix.
Now that the Obama administration is proposing a national clearinghouse of public domain, for-credit online courses, the question of national accreditation is starting to rear its head.
Typically, regionally accredited institutions only take transfer credits from other regionally accredited institutions. That's why, for example, the state colleges and universities take our credits in transfer. (Transfer is always subject to fitting the intended program, so a student who switches majors may lose a bunch of credits, but that's another issue.) Otherwise, it would be all too easy for some fly-by-night operation to become an outsourced diploma mill under the protective cover of someone else's accreditation.
In the 'national database' model, as I understand it, no particular college would 'own' any of the courses. They'd all be in the public domain, graded by...uh...well, never mind that, but they'd be shared. Since no particular college owns the courses, it's not at all clear whose regional accreditation would attach to them. Regionally accredited colleges and universities would be asked to accept credits without regional accreditation.
Presumably, this is easily patchable with some sort of fiat. But the larger issue is whether regional, as opposed to national, accreditation still makes sense. This may be the catalyst for a serious discussion about revisiting the regional accreditation model in toto. In the age of online learning, electronic communications, and an increasing federal role in higher ed, does the regional model even make sense anymore?