The history of the people, problems, and politics surrounding the establishment of federal special education policy is rich with useful illustrations for advocates and educators. As the 50th anniversary of IDEA approaches, we use a historical perspective to consider how the promise of the law -- to ensure access to a free appropriate public education for students with disabilities -- is advanced through rational inquiry, the exercise of democracy, and specially designed instruction that prepares young people for living dignified and productive lives. We reflect on the spirit of the law when it was written, and on successes and challenges to its promise over time in envisioning an optimistic future for special education.