The teachers’ unions blockade, which deprives poor children of good education, is starting to crack.

The latest fissures are created by a study of the country’s largest private school choice program. According to researchers, the Florida Tax Credit Scholarship program, which provides vouchers, increased college enrollment rates by about 6 percentage points for students who participated at all. For those who were in the program for four or more years, the college enrollment rate was as much as 17 points higher.