In 1988, teachers union leader Albert Shanker had an idea: What if teachers were allowed to create a school within a school, where they could develop innovative ways to teach dropouts and unmotivated students? The teachers would get the permission of their colleagues and the local school board to open their school, which would be an R&D lab for the regular public school. These experimental schools, he said, would be called “charter schools.”

Five years later, in 1993, Shanker publicly renounced his proposal. The idea had been adopted by businesses seeking profits, he said, and would be used, like vouchers, to privatize public schools and destroy teachers unions. He wrote that “vouchers, charter schools, for-profit management schemes are all quick fixes that won’t fix anything.”

Shanker died in 1997, too soon to see his dire prediction come true. Today, there are more than 7,000 charter schools with about 3 million students (total enrollment in public schools is 50 million). About90 percent  of charter schools are nonunion. Charters are more segregated than public schools, prompting the Civil Rights Project at UCLA in 2010 to call charter schools “a major political success” but “a civil rights failure.” They compete with public schools instead of collaborating. Charter proponents claim that the schools are progressive, but schools that are segregated and nonunion do not deserve that mantle.

The charter universe includes corporate chains that operate hundreds of schools in different states. The largest is KIPP, with 209 schools. The-second-largest has 167 schools and is affiliated with Turkish preacher Fethullah Gulen. About one of every six charters operates for profit; in Michigan, 80 percent  are run by for-profit corporations. Nationally, nearly 40 percent of charter schools are run by for-profit businesses known as Educational Management Organizations.

The largest online charter chain, K12 Inc., wasfounded with the help of former junk-bond king Michael Milken and is listed on the New York Stock Exchange. The biggest single virtual charter was the Ohio-based Electronic Classroom of Tomorrow, which collected $1 billion from Ohio taxpayers from 2000 until its bankruptcy earlier this year. The charter’s 20 percent graduation rate was the lowest in the nation. ...