There is no one with authority to judge a Guardian:

It is questionable who has the authority to judge a Guardian in regards to matters related to the Cause; to say in this case or that case he made a mistake? We have seen in T.R.B. some comments that Shoghi Effendi made a mistake because he did not announce his successor more clearly than he did or that Mason Remey made a mistake because he delayed making his proclamation or similarly why did Joel B. Marangella wait so long to issue his proclamation? My answer is: those things or similar things had to happen. They were guided to do it the way they did. If Shoghi Effendi trusted Rúhíyyih Khánum, he did not make a mistake as she was a Hand of the Cause and also his secretary. Moreover, she was his wife, and all of the records of her writings prior to the passing of the first Guardian reveal to the reader her profound knowledge of the Faith and the Covenant and emphasize her clear testimony to the necessity of the continuation of the Guardianship until the end of the Bahá'í Dispensation. If Rúhíyyih Khánum after the passing of Shoghi Effendi followed the satanic promptings of her human soul, that was her great error which made her the "Arch Covenant-breaker." The Guardians are not prophets. Some people claim that the Manifestations of God have made a lot of mistakes (which is not true), the fact is that we cannot judge those things that have been done or have happened in the past according to today's knowledge and understandings and conditions. We cannot blame Jesus for what He did with the businesses in front of the Temple, which by today's laws would be considered a crime. He did what He had to do then according to the Will of God. Some people have raised questions as to why Shoghi Effendi put so many of his relatives out of the Faith. The fact is that the condition of the Faith in its infancy required a non-tolerant discipline and on the other hand those relatives' exploitation and misuse of the privileges that they possessed was not acceptable and they left no other choice for the Guardian. He did what he had to do according to the Will of ............. Click for detail

By Hand of the Cuase of God Nosrat’u’llah Bahremand