As predicted, Trump just fired Berman. https://www.foxnews.com/politics/william-barr-trump-fired-sdny-federal-prosector Many have suggested that Berman could refuse on the basis that he was appointed by a court. That is a dubious constitutional position given the separation of powers doctrine... https://jonathanturley.org/2020/06/20/barr-v-berman-manhattan-u-s-attorney-refuses-to-leave-office-after-announced-replacement/

...the DOJ has long rejected that position and the majority of the Supreme Court would likely agree. There still remains the question of the reason for the action in the first place. Given the Trump-related investigations, Barr owes the public an explanation.

...President Trump has said that he was not involved in the decision, which was made by Barr. Once again, this only magnifies the importance of an explanation. This is not clearly connected to the Trump investigation but there is a valid concern that it could be.

Barr's letter denies that this change will have any impact on pending cases: "Your statement also wrongly implies that your continued tenure in the office is necessary to ensure that cases now pending in the Southern District of New York are handled appropriately ...

...This is obviously false. I fully expect that the office will continue to handle all cases in the normal course and pursuant to the Department’s applicable standards, policies, and guidance." This again suggests that there was another reason for the move...