According to producer-director Peter Gilbert (Hoop Dreams), four small words marred the U.S. Supreme Court’s landmark 1955 order to desegregate America’s schools: With All Deliberate Speed. Purposefully vague, the qualifier essentially nullified the Court’s momentous Brown v. Board of Education ruling of the previous year — South Carolina’s Dillon County didn’t integrate until 1970 — and its legacy continues to adversely affect schools today. The doc powerfully reconvenes players from two of the five cases that snowballed into Brown, highlighting ”unsung heroes” like Charles Houston. Dean of Howard University’s law school in the 1930s, Houston strove to produce a generation of astute legal minds (Including Brown counsel/future Supreme Court Justice Thurgood Marshall) in hopes of preventing an equal rights movement dependent on any one activist. The film’s one misstep: using modern celebs to voice trial and diary excerpts. While Alicia Keys, Mekhi Phifer, and Larenz Tate break up the string of talking heads, they lack the poignantly honest recollections of the era’s actual participants.