In a strongly worded caveat in the book, Witte emphasizes that because the free-market theories behind choice require that bad choice schools be closed once parents opt not to send their children there, "voucher schools will not always be shining, innovative havens from the public school system that advocates for choice make them out to be."

Witte's biggest concern is the eventual spread of school choice to all students, regardless of their income, once again abandoning poor students who originally were to benefit from choice.

He suggests that the most likely path for Milwaukee and other voucher programs will be "that a program originally intended to target choice on poor inner-city families is manipulated over time to produce the opposite results — subsidies for middle-class, non-inner city families to make choices they would have made on their own.

Witte justifies his concerns that Milwaukee's voucher program is intended to grow to a full-scale, universal program by citing a 1988 plan proposed by Gov. Tommy G. Thompson. The program, which was killed from the state budget bill, would have applied to all private schools in Milwaukee County without any limits on the number of children participating.

Darren Schmitz, an aide to Thompson, said the governor has no intention of expanding the program right now.

"There is no conspiracy movement at work here," Schmitz said. "The governor designed school choice to help low-income kids get the education they deserve,"

Witte suggests that although he believes Milwaukee's program might represent a slippery slope toward a universal voucher system, that alone is not enough to convince him that the program isn't good public policy. Describing a conversation he had with former Milwaukee Superintendent Howard Fuller, he writes that he agrees with Fuller that some type of "bomb" probably is needed to prod inner-city school districts.

"A targeted (voucher) program may not provide a bomb, but it will serve as a constant reminder and even irritant for those systems," he writes. "It will also serve as a policy alternative for some families, aid private schools as needed alternatives, and perhaps increase cooperation between the public and private schools sectors."

He also concedes that he could be wrong about the motives of choice backers. He describes giving testimony to the Legislature in 1995 in which he described his concerns about the program spreading beyond low-income children. The committee chair, Sen. Peggy Rosenzweig (R-Wauwatosa), and other Republicans appeared to be listening most closely to his concerns.

"None (of the Republicans) present argued for the abandonment of public education, and all present understood the cost implications of a universal voucher plan," he wrote. "Thus that slope may not be as slippery as I first thought and testified."

Rosenzweig recalled that the hearing involved a state audit showing that there was no "creaming" of the best students by the choice program. She said she and her colleagues were very interested to learn that the students who were participating in the program generally were low-income and required academic help.

"I think it is safe to say it is not our intention to expand the program (universally)," Rosenzweig said.

Throughout the book, Witte attempts to remind the reader that often there are not clear answers to every question.

For example, he notes that Milwaukee's choice program has been successful in fulfilling its main design: to provide an opportunity for poor parents to send their children to schools of their choosing. At the same time, he notes that if those students had remained in public schools, their parents could have used their anger against the school to improve it.

Like many who have observed private schools in the choice program, Witte concludes that choice schools are like public schools in that some are excellent, some are mediocre, and some are poor. Those similarities to public schools do not make the program a failure.

"Parental satisfaction increased," he writes. "In addition, some students did very well, while on average choice students achieved about as well in terms of national standards as where they began."