sentences:  By this time, however, the once-radical ideas of progressive education had become "conventional wisdom" and kindergarten was a ubiquitous feature of American public schools.As part of Malach's "bid to reforge the leadership role that Avery Coonley School had played during its early years", ACS joined the Independent Schools Association of the Central States (ISACS) in 1961.ISACS was founded in 1908 to promote best practices in independent schools, and instituted a mandatory accreditation program for member schools in 1961.