Aside from street protests and rallies (which NG should scrupulously facilitate for 1A reasons; DC itself has been fairly bad about this in the past, too), I don't think most local policing is highly political. Yes, DC residents are losing some democratic control over their local policing, which is bad, but DC has also done a bad job with local policing for a long time.
(I'm broadly in favor of shrinking DC to the federal areas themselves; the parts where people live generally should be returned to the States.)