“In the long run, charter schools are being strategically used to pave the way for vouchers. The voucher advocates, who are very powerful and funded by right-wing foundations and families, recognize that the word voucher has been successfully discredited by enlightened Americans who believe in the public sector. So they’ve resorted to two strategies. First, they no longer use the word “vouchers.” They’ve adopted the seemingly benign phrase “school choice,” but they are still voucher advocates.” — Jonathan Kozol
The end goal of school privatization projects like charter schools has always been vouchers. While both charters and vouchers prevent the public from being able to control the curriculum taught with public dollars, vouchers are far worse in that regard. Vouchers represent an attack on democratic institutions and they represent an attack on rationality in general. Espinoza v. Montana Department of Revenue, a case about to be heard in front of the Supreme Court of the United States (SCOTUS), could open the flood gates to scare community tax dollars being squandered on dominionist curricula and schools that can openly discriminate.
With a SCOTUS populated by arch-reactionaries like Kavanaugh and Gorsuch, it's highly likely that the Establishment Clause of the First Amendment will either be ignored or explained away in order to justify funding extremist religious organizations. You know Espinoza v. Montana Department of Revenue represents a major threat to public education when charter-voucher promoting organizations like the Center for Education Reform file an amicus brief in favor of the right-wing plaintiff. Reactionaries Jeanne Allen and Paul Clement also got a piece published in Time in favor of using public funds to teach religious extremism.