According to The Hill, "Byrd’s health has been a question all year. He was hospitalized three times, prompting some of his colleagues to question whether he was up to one of the most demanding and important roles in the Senate.In April, Byrd moved to quell his critics by chairing a hearing on the Iraq war and afterward telling those who questioned his capacity to 'shut up.'" The soon-to-be 91 year old Byrd will be replaced by the youthful Daniel Inouye (D-HA), only 84, who will be moving from Commerce.
Byrd's actions have set off a game of musical committee chairs for the Democrats as Jay Rockefeller (D-WV) will jump from Intelligence to chair Commerce, and Diane Feinstein (D-CA) will take over at Intelligence. This in turn will open up the chair of Rules and Administration for Chuck Schumer (D-NY).
Vice President-elect Joe Biden's departure from Foreign Relations could mean that John Kerry (D-MA) or Russ Feingold (D-WI) could end up chairing that panel. Expect all the changes in Senate chairmanships to be informally in place well before the 111th Congress comes into session January 3.