Potter Stewart

“ These factors are said to 'betoken a state, rather than a private, instrumentality.' The question, however, is not whether the District is a state instrumentality, but whether it is a 'political subdivision' of the State. And the provisions in question hardly go to that issue.
The Board's reasonable construction of the Act is entitled to great weight and it is not our function to weigh the facts de novo and displace its evaluation with our own. The Board here has made a reasoned decision which does not violence to the purposes of the Act. ”