As happens in most challenges to private school choice programs, a coterie of groups representing the state education establishment’s interests argued that the program violated constitutional provisions against public support for religious institutions (commonly known as Blaine Amendments).
The court, simply and plainly, as numerous state courts and the US Supreme Court have before, rejected this argument, and upheld the constitutionality of the program.
From paragraphs 11 and 12 of the judgment (emphasis mine):
The ESA does not result in an appropriation of public money to encourage the preference of one religion over another, or religion per se over no religion. Any aid to religious schools would be a result of the genuine and independent private choices of the parents. The parents are given numerous ways in which they can educate their children suited to the needs of each child with no preference given to religious or nonreligious schools or programs. Parents are required only to educate their children in the areas of reading, grammar, mathematics, social studies, and science.
The ESA is neutral in all respects toward religion and directs aid to a broad class of individuals defined without reference to religion. The ESA is a system of private choice that does not have the effect of advancing religion. Where ESA funds are spent depends solely upon how parents choose to educate their children. Eligible school children may choose to remain in public school, attend a religious school, or a nonreligious private school. They may also use the funds for educational therapies, tutoring services, online learning programs and other curricula, or even at a postsecondary institution. We therefore concur with the trial court that the ESA does not violate the Religion Clause.
Couldn’t have put it better myself.