The fixed cost argument: School choice would lower the revenue to public schools. Since public schools have large fixed costs, school boards will have to raise taxes to cover these costs.
Every business has fixed costs. Managing and controlling fixed costs is part of making a business efficient. There is an easy place for public schools to “cut fat” and reduce their fixed costs: non-teaching overhead.
In 2007 Texas public schools spent only 41% of their operating expenses on teacher salaries. (TEA Snapshot 2012 Summary) I would expect that the non-teaching 59% of the budget could be trimmed somewhere.
That is one of the big benefits of school choice, it will force public schools to economize rather than raising taxes for more administrators and administrative buildings.