The phrase
"unfettered control" means having complete and unrestricted power or authority over something or someone, without any limitations, restrictions, or obstacles.
Full definition
Districts then had
nearly unfettered control over how these funds were spent; activities merely had to comport with four major federal education statutes, including the Elementary and Secondary Education Act — laws that, despite many years and billions invested, hadn't adequately improved our schools.
As the event page notes, ESAs give families almost
unfettered control over the public funds allocated for their child's education.
Rauner has noted Democrats had
unfettered control of state government for a dozen years but failed to change the school funding formula.