Board Of Education - Tumblr Posts
So I figured out the name of the law that granted the District the right to elect its own board of education: District of Columbia Elected Board of Education Act, approved April 22, 1968; Public Law 90-292, 82 Stat. 101. This link is President Johnson's remarks upon signing the bill.
It's important to note that Dr. King was assassinated on April 4; riots erupted in Washington and continued through April 12. After some public uncertainty about whether the protest would continue, the SCLC's Poor People's Campaign began on the National Mall on May 12. This is the atmosphere in which this bill was signed, and it's equally important to note that after an oblique reference to the city "in crisis," President Johnson openly calls for congressional representation and home rule for the District.
This GPO pamphlet also seems like it may be important later on, although I'm unsure of how to use it now.