The downside of charter schools

When it comes to the various forms of school choice, this blog has generally been a big tent (note, for example, the many posts under the labels "Charter Schools" and "Virtual Schools"). But Cato Institute scholar Adam Schaeffer pointed out something yesterday that I think needs to be highlighted:

Charter schools often provide a safer, better alternative to traditional public schools. That’s good. Charter schools also destroy private schools, decrease educational options, pull private-school students into the government education system and thereby add significant new costs to taxpayers.