Even though the letter of excommunication that the Gra signed is legally valid, and in fact people that ignore it come under the curses that are listed for anyone is transgresses a oath (or in this case a חרם); still I do not feel that Breslov comes under that category. The reason is while I was wandering around the Old City of Jerusalem I stumbled upon a book that brought the original documents word for word. [That included the other letters of excommunication, and also the statements of the witnesses that were collected in Villna and written down.]
But as the actual issues of Breslov, I think that there should be made a distinction between ideas that the Ran held strongly with and ideas that were less sure [or more doubtful what he actually meant]. I.e. there were things he held very strongly were correct like the saying the ten psalms.
The idea that transgressing a חרם [excommunication] is the same kind of thing as transgressing an oath I got from the regular commentaries of the Rambam right on the page in Laws of Oaths. And the general warnings about transgressing an oath are pretty explicit.
But as the actual issues of Breslov, I think that there should be made a distinction between ideas that the Ran held strongly with and ideas that were less sure [or more doubtful what he actually meant]. I.e. there were things he held very strongly were correct like the saying the ten psalms.
The idea that transgressing a חרם [excommunication] is the same kind of thing as transgressing an oath I got from the regular commentaries of the Rambam right on the page in Laws of Oaths. And the general warnings about transgressing an oath are pretty explicit.
