The Supreme Court’s jurisprudence does not provide easy answers to these questions, and the relevant body of case law is inconsistent......
Consider, for example, the four existing voucher statutes that allow for the participation of religious schools. Ohio’s statute only requires that participating schools “not discriminate on the basis of race, religion, or ethnic background.” 12 It further mandates that schools not “teach hatred of any person or group on the basis of race, ethnicity, national origin, or religion.” 13 Florida’s program requires schools to comply with Title VI, which only bans discrimination on the basis of race, color, or national origin. 14 Wisconsin’s voucher statute contains the same requirement. 15 Civil rights advocates in Wisconsin have been unsuccessful in their repeated efforts to include a more comprehensive anti-discrimination policy in that state’ s voucher law, despite the fact that Wisconsin public schools are held to one of the most expansive anti-discrimination laws in the nation. 16 Colorado’s voucher law—the most recently enacted of voucher laws—bans discrimination in participating schools only on the basis of “race, color, religion, national origin, or disability.” 17 A vague but potentially expansive provision of Colorado’s law also bans schools from “teach[ing] hatred of any person or group.” 18
Most proposed voucher bills include civil rights protections that would ban discrimination by voucher schools on the basis of race and national origin but do not contain provisions banning discrimination based on religion or sexual orientation. 19 One obvious explanation for this pattern is that discrimination against religious groups or gays and lesbians is more often considered justified by religious teachings, and legislators wish to respect religious schools’ rights to free exercise of religion. Another obvious explanation for the exclusion of sexual orientation is simply that in many parts of the country such discrimination is still socially and politically acceptable, regardless of whether there is a religious motivation. Despite these obstacles, legislators concerned about civil rights have not given up on efforts to include classifications like religion and sexual orientation in voucher laws. 20
Voucher legislation also tends not to ban discrimination based on sex, 21 perhaps because of the common—though certainly not universal— acceptance of single-sex schools as consistent with anti-discrimination norms. Some voucher legislation not only lacks civil rights protections altogether, but also includes provisions that could, among other things, affirmatively protect a school’s “right” to discriminate. For example, voucher legislation proposed in Kansas includes a provision stating that “[n]othing in this act shall be applied or construed in any manner so as to regulate or prohibit free exercise in matters of curriculum, creed or practice of any nonpublic Kansas school of choice.”
Opposition to vouchers is driven not only by legislators’ tendency to exclude comprehensive anti-discrimination provisions from voucher proposals, but also by a fear that private schools would be constitutionally exempted from anti-discrimination policies even if legislatures attempted to impose them. .....
In 2000, the Supreme Court held that the free speech right of expressive association exempted the Boy Scouts of America from New Jersey’s public accommodations law banning discrimination on the basis of sexual orientation. 28 It is still unclear how broad Dale ’s reach will be. If it does extend into the realm of private schools, the consequences for antidiscrimination laws and voucher programs may be enormous. Voucher schools, like the Boy Scouts, may argue that their discriminatory practices entail the constitutionally protected expression of their viewpoints, and that this free expression may not be burdened or disfavored by the government.........."
http://www.yalelawjournal.org/images/pdfs/375.pdf (bold type added by Hard Truth)