Financial aid given indiscriminately to all parents of school children (whether in public or religious schools) has tended to pass muster when challenged in court. If the aid is limited or directed to only parochial schools, it will generally fail for inability to show that the aid or assistance was limited to a non-religious purpose.
Paying bus fares and lending secular text books to parochial and private schools do not violate the Establishment clause. However, direct grants, including the supplementing of salaries is prohibited.
