So ends the strangest game of musical chairs in TV history. Katie Couric deposes Deborah Norville, who deposed Jane Pauley (see story and requisite kissy-face denials of ruthless behavior on page 72). Is Today running a news show or a popularity contest? Both Couric and Norville are talented and capable. Their faults cancel each other out. Couric can be impatient in interviews (as when she plowed through Tony Horwitz, author of Baghdad Without a Map), while Norville, in her 17-month reign, was simply too brisk and bright-eyed for those muzzy morning hours. More important, she never escaped a public perception that it was she, and not myopic NBC execs, who shafted Pauley. The ratings increase when Norville went on maternity leave had less to do with a groundswell of Couric support than it did with remarkably obdurate anti-Norville sentiment. Never have the Nielsen families seemed so vindictive. In fact, this morning melodrama has resembled nothing so much as a homecoming queen election at a very catty high school.