What is the fine-grained topic of the following text: The commenter, who calls himself Ajay Bruno and claims to be Stephanie Herseth’s chief of staff, Jeff Navin holds that position by the way, is now saying that he has resigned from the Herseth campaign and will be supporting her challenger Bruce Whalen. Only return the topic.
Ajay Bruno's alleged resignation from Stephanie Herseth's campaign and subsequent support for Bruce Whalen.