Aaron Sorkin’s already-anticipated HBO pilot More As This Story Develops (still just a tentative title, thankfully) has just added a sober voice of reason in Sam Waterston, who will play the network president tasked with keeping an eye on Jeff Daniels’ grandstanding news anchor. It’s a fitting role for Waterston, who over the years has put his reassuring tones and gentle authority to good use in everything from sussing out murder cases on Law And Order to recommending sound investments via those Ameritrade commercials to warning old people about robots trying to steal their medicine.