Newsweek's Michael Hirsch is hearing rumblings:

Joe Biden was going to be John Kerry's secretary of State. "That was what we were led to believe" before Kerry lost to George W. Bush in '04, says an aide to the Delaware senator, who is chairman of the Foreign Relations Committee. Now Biden, who has been to foreign policy in the Senate what Ted Kennedy has been to domestic policy (almost anyway!), is emerging as a major consigliere to Barack Obama—perhaps with his eye on State once again. Among the top items on Biden's agenda: making sure that Obama has better luck in November than Kerry did. That means, first, relentlessly attacking and counterattacking the Republicans on the campaign trail, especially on national-security issues. And, second, relentlessly defining John McCain as "joined at the hip" to Bush, as Biden put it in a speech in Washington on Tuesday. Read more...