Trust in parents isn't the issue. Trust in politicians is.
The Indianapolis Star argues for private school vouchers because we should trust the parents of children getting vouchers. I would submit that trusting parents is not the issue. Trusting politicians is the issue, and a reason why supporters of Christian schools should be wary about giving taxpayer money to those schools.
I've said this before in letters to the Star. I trust the parents, but I don't trust the politicians. I do not trust that the fact that private schools get tax money will not be used to force those schools to operate the way the state sees fit. Will Christian schools be forced to hire atheists, homosexuals or Muslims as teachers? Will Christian schools be forced to eliminate Bible classes and chapel services, or use secular science textbooks that focus on evolution?
This is not to say I agree with all of the arguments of voucher opponents.
I do not see a problem with the constitutionality of vouchers. The question is whether the money is used for the benefit of religious institutions (as prohibited in Article 1 Section 6) or whether the state is simply subcontracting work to the private sector - as the state did with the lease of the Indiana Toll Road. Simply subcontracting education to the private sector without discriminating on the basis of religion is not a violation of the state constitution, in my opinion.
Furthermore, as the Star points out, the predictions of dire financial consequences to government schools are a little overblown. There are many legitimate questions about whether government schools need as much money as they get, in any case.
The primary reason conservatives should oppose vouchers is because of the potential for government interference in private schools. Twenty years ago, I began my senior year at Grace Baptist Academy in Angola, Indiana. I am very thankful for this experience and I do not want to see today's students lose the opportunities I had through meddling by politicians. If Christians want to see more students in Christian schools, then private scholarships are the answer - not the narcotic of government money.