There are a few different agruments that tend to be used on both the pro and the con side of the debate, and if you have internet access (and therefore are reading this) you can look them up easily on your own. While I am hesitant to muck with education funding any more than we currently are, I can see some merit in the basic concept of vouchers (though I did vote against them when they came up on a ballot). But there is one argument that seems to be the standard argument for those who are in favor of a voucher system and I have always thought it was a poor argument.
Okay, so, to not get too far ahead of myself: the standard argument that I have heard in favor of school vouchers is based on an old and overly-simplistic market economic model. Put simply the argument is this:
If a voucher system is in place, then schools will have to compete for funding, which will result in schools that fail closing down, and improved performance on the part of other schools as they compete with each other. Therefore, a voucher system will result in the education system improving overall, cutting out the deadwood and performing in a more efficient and productive manner.
Now, there's a few problems with this argument, the first of which being that there are many ways that schools can become more efficient and improve test scores while not actually educating students particularly well - the ol' "teaching to the test" issue. There's also the fact that this turns all schools into businesses with funding potentially coming before students. While it could pay off in the end, this is admittedly me being literally conservative in wanting to avoid what I think is unnecessary change to an important institution, there is a possibility of introducing an increased risk of financial corruption - We have seen such things in every other for-profit business, so why not here?
But, to my mind, the biggest flaw in the argument is that it assumes that parents will send their children to the school that bests educates them. Based on what I have seen from both private schools and home-school settings, I don't see any reason to assume that this will be the case.
Here's the basic problem - there are a lot of people in the world for whom ideology is more important than observable reality. These folks may be a minority, but they are a sizable minority. These are the people for whom ideology, usually political or religious ideology (often the two mixed together) is the arbiter of what they believe, even when it contradicts the pbvious facts of the world around them. And if vouchers are the reality, then these folks would be likely to seek schools that cater to their pre-conceptions and therefore not only fail to educate their students, but actually misinform in ways that range from the silly to the dangerous.
Creationism and Christian Nationalism are the most obvious examples of demonstrably false beliefs being taught already in private schools and home schooling programs (and, if the current Texas school board has its way, in public schools). I rant about them frequently already (in fact, a post ranting about them dropped last week), so let's try some other beliefs...
Consider, for example, that I know many people who are completely convinced that the Americas were settled not by people who crossed over from Asia 10,000 - 13,000 years ago, but by some other group of people at some other time. For some, such as the LDS (Mormon) church, this is a matter of religious dogma. For others, it's part of a conspiracy-mongering ideology that holds that all actual history is some sort of plan to dupe the populace. For others it is part of a racist claim to "white racial ownership" of the Americas. The effects of such belief on public policy should they become commonly taught are hard to say - certainly the racist views would be harmful, but some of the other views might simply be absurd. But regardless, there is nearly two centuries of archaeological and physical anthropological data, and increasing amounts of genetic data, showing all of these beliefs to be completely and utterly false. Students taught this in schools are not being well educated, and yet there are many people who would happily send their children to a school that taught such things, and many other people who simply wouldn't care if their children attended a school that taught such things. And yet the children would be astoundingly misinformed, and the education system would, by definition, not be working.
Let's take another example. I know many people associated with the home schooling movement who believe that modern medicine is a sham by major companies to keep the populace sick and take their money and/or control their minds, and that modern doctors don't actually know anything about preventative care. Aside from being paranoid in the extreme and completely out of touch with reality, this sort of belief also has another problem in that it sows the seeds of an unhealthy populace. People who reject scientific medicine don't just reject what are admittedly often troublesome or even downright dirty action on the parts of pharmeceutical companies, they also reject the methods that have proven reliable over the last two hundred years in identifying and either eliminating or else mitigating the causes of illnesses, steadily improving our cultural ability to cope with biological hazards. It is no surprise that the pockets where these sorts of beliefs have taken hold, whether it be the (not really all that) venerable Christian Scientists or followers of various New-Age paths, have become hotbeds for resurgences of previously near-eradicated disease. Moreover, by teaching that physicians and researchers are not to be trusted, these beliefs have, at least in my experience, had the tendency of teaching their followers (and the children of said followers) that facts don't matter in determining reality, and knowledge is only a lesser cousin to emotional appeal in determining the validity of a claim.
So, again, parents who buy into this but who are currently unable to put their kids into home-schooling (and I know many such people) would, with the vouchers, be able to use the education system as a tool to spread false and dangerous beliefs that are likely to create a public health risk.
Many people are probably going to say that I am being paranoid. Maybe they're right, but I don't think so (well, I guess it's rather obvious that I wouldn't think so, being as how I'm the one advocating this position and all). I am now at an age where many of my old friends have school-age children. I have found that most of these people tend to expect that their children's textbooks will be well-researched, and the teachers well-trained. And so, if they are sending their children to school, they will assume that what the child learns is more-or less accurate. It is generally the more zealous folks, driven by ideology rather than an attachment to reality, that will question what is taught in schools, but they will question it for all of the wrong reasons and in all of the wrong ways. As a result, these folks, it seems, would be more likely to look into changing their childrens schools if it were to become feasible to do so. So, rather than an improvement to the schools, with well-run schools with a good curriculum becoming more common, we'd likely see schools run for ideological reasons becoming more common. The economic argument just seems like a very poor one.
However, perhaps I am completely wrong. So, here's what I will do as time allows, I will start looking into school districts where vouchers have become part of the system. I'll see, if such information is available, what types of schools thrive in that environment. And in a few months time, I will write a follow-up with what I find.
And I hope that I am wrong.