I heard a good discussion on this on NPR yesterday. On the one hand the Presidents use of twitter one could argue is like a town hall meeting where 1st amendment rights should be enforced. On the other some argue that its his personal twitter account and he should be able to block anyone he wants. This could get interesting in terms of the SCOTUS and the use of social media by Pols in the context of 1st amendment issues.
https://www.bostonglobe.com/news/nat...jTM/story.html