One of the primary organizations involved directly in fighting vouchers for religious schools is Americans United for the Separation of Church and State. www.au.org Here’s their page on religious school vouchers:
http://www.au.org/issues/religious-school-vouchers/
AU’s position is that vouchers are a government subsidy to churches, in violation of the First Amendment’s Establishment Clause.
I wouldn’t think busing counts, though. Since it’s not really going to the school, per se. More as, all parents pay taxes, therefore, all students have access to busing, no matter what school they go to.
IMHO, yes, it does. It frees up budget resources for the private school, and adds yet another cost to the public ones.
The “all parents pay taxes” argument forgets that everyone, regardless of parental status, pays taxes. It’s supposed to support the notion that everyone benefits from the existence of free public schools.
I will cease to elaborate as this would head down the path into another forum.