How is that a problem? The parochial schools are academically superior, at least compared to the inner-city schools run by public unions. And America is very religious for a western nation so it is not a political handicap.
On the latter point, it's not a political handicap as long as religions Americans like are getting the taxpayer money for their schools, but once religions Americans don't like qualify for the programs, support starts to dry up: http://www.huffingtonpost.com/2012/06/13/louisiana_n_1593995...
There's a number of problems. One is that it's whackjob fundamentalists that want to use this simply to isolate their children from reality. Another is that there's so many religions that just don't quite agree & wouldn't want their money going to a Baptist/Catholic/Jewish/Mulsim/Hindu/Scientologist/Mormon/whatever school. Finally, and most importantly, there's the 1st Amendment which provides for separation of church & state & putting any state money towards religious education is a clear violation of this principle.
