(CBS News) WASHINGTON - There's suddenly a lot of talk about possible tension between President Obama and Vice President Biden.
When Biden seemed to break with the president and endorse gay marriage Sunday, he set off Washington's talking heads. Was it a deliberate signal to the gay community? Or was it just Biden in yet another unscripted moment?
In a speech Tuesday, the vice president addressed his tendency to say whatever's on his mind. "No one's ever doubted I mean what I say. The problem is, I sometimes say all that I mean," he conceded, to laughter.
In that speech, to a conference of rabbis in Atlanta, Biden also demonstrated, however, why he's an effective spokesman for the Obama administration, saying, "I hope, by now, no one doubts that the president is willing to use power. The president's smart."
But the vice president's latest off-the-cuff moment showed that he can also be a liability - which is not news to the White House.
He can be exuberant - as he was when the president's healthcare bill finally passed Congress, whispering to Mr. Obama, "this is a big [expletive] deal!"
He can be careless, as when he joked about Chief Justice John Roberts flubbing the presidential oath Roberts administered to Mr. Obama. Biden quipped to reporters, "My memory is not as good as Justice Roberts'."
And he can be brutally honest, maybe too honest - even about himself.
For instance, Biden admitted in September 2008 that, "Hillary Clinton is as qualified, or more qualified than I am to be vice president of the United States of America. ... And quite frankly, it might have been a better pick than me."
Sometimes, the president himself weighs in on Biden's impromptu remarks.
In February 2009, Mr. Obama said, evoking laughter from reporters, "I don't remember, exactly, what Joe was referring to. Not surprisingly!"
The New York Times reports that the jab annoyed the vice president, who brought it up to the boss one day over lunch.
But their relationship is close. Biden is one of the few people beyond his own circle the president has come to trust - and Mr. Obama sees him as someone who relates both to blue collar voters and to Biden's longtime former colleagues on Capitol Hill.
It's a relationship so close that the president, joking with reporters at the recent White House Correspondents Dinner, edited out a quip about whether Biden would remain on the ticket in 2012.
Comedian Jimmy Kimmel filled the void at the same dinner, telling the audience, "It's kind of hard to be funny with the president of the United States sitting right next to you and looking at you. And yet, somehow, day in and day out, Joe Biden manages to do it!" The remark drew loud laughter.
So, what are the chances of the president picking another running mate? Zero, according to people around the White House. Look for Biden instead to play the role usually assigned to someone in his position. In the campaign, he'll be on the attack, while the president takes the high road.
To see Bill Plante's report, click on the video in the player above.