Updated

"I think it's fair to say I was just too polite…”

-- President Obama in an interview with radio host Tom Joyner.

An incumbent president whose campaign has called his challenger a “vampire,” a “liar” and a possible “felon” ought not need to apologize to his supporters for excessive politeness.

But, despite running the most intensely negative re-election campaign in presidential history, Barack Obama is scrambling to prove to dispirited Democrats that he is willing to be nasty.

The bloodlust in the Democratic base following the shellacking Republican presidential nominee Mitt Romney laid on the president in last week’s debate has become intense. Obama has flattered himself by saying the reason he got so badly beaten was because he was too respectful, too honest and too focused on the issues.

More On This...

Now, the president promises that he’s really ready to get nasty.

It is unfortunate for Democrats that this pledge of a new incivility came just ahead of tonight’s vice presidential debate. Obama’s running mate, Joe Biden, has always struggled with his tone and his command of the facts and hardly needed any encouragement to act as a blunt instrument in his big moment of the campaign.

It seems amazing that Democrats would need reassurance that their candidates would play rough. Biden, after all, warned a mostly black audience that Republicans wanted to put them “back in chains” and said that Romney wanted to make “suckers” of middle-class voters.

Republicans had ample reason to worry whether Romney would press the incumbent during the first five months of the campaign, but it’s odd that Democrats would worry that a campaign that will spend much of its $1 billion war chest on attack ads and repeatedly level stinging personal accusations against Romney doesn’t have the taste for blood.

But, in part because of Obama’s repeated claims that his restraint and focus on policy over politics are to blame for the ticket’s troubles, Democrats are demanding more venom and less restraint.

As he hits the stage tonight, Biden will be the beneficiary of very low expectations. His gaffe-filed tenure and over-the-top style have made him something of a political curiosity. Obama has frequently reinforced the notion of his number two being comic relief, famously calling him “Sheriff Joe.”

Biden’s opponent, Paul Ryan, meanwhile will be struggling under high expectations. He is the leading light of the Republican Party on fiscal policy and famed as a wonk with a dazzling command of the facts.

Biden, most famous for an overheard f-bomb at the signing of Obama’s controversial 2010 health law, will be applauded if he manages to get through tonight’s showdown without profanity or some other massive gaffe.

[pullquote]

Ryan, conversely, will be judged to have missed expectations if he does not make chop suey of the overmatched incumbent. Ryan is 27 years younger than the 69-year-old Biden and is a 14-year member of the House rather than a 36-year veteran of the Senate, but Biden’s many, many missteps still make Ryan the favorite in their bout.

Had Romney not beaten Obama so badly, Biden might have managed to sort of skate through the debate leaning on a few folksy tales and some humor to get by. “Sheriff Joe” would have been judged the winner as long as there were no catastrophes.

But with Democrats screaming for revenge, Biden is in dangerous territory.

The latest FOX News poll shows something few would have predicted at the start of this election cycle: Voters’ favorable impressions of Romney and Ryan are higher than either of the counterparts.

We have been told ad nauseum how much more likable and relatable the Democratic candidates are than their cold-blooded Republican counterparts. But Romney edges Obama on favorability in the latest poll and Ryan is way ahead of Biden, scoring a +8 to Biden’s -3.

Much of this is consequence of the Democrats’ campaign strategy focusing on personal attacks. Having not talked much about “the vision thing” other than to ask Americans to stay the course, Obama and Biden have mostly been whacking away at their challengers. Political attacks always do damage to the attacker, but the hope is that the one being attacked suffers more. The race today suggests that Obama has, so far, failed in that mission.

If Biden feels obliged to show himself red in tooth and claw as he debates the respectful, serious young Ryan, it will certainly reinforce the notion that the core Democratic message this year is that they really, really hate Republicans. The Democrat pre-spin that Ryan “lies” suggests that’s where tonight’s goat roping is headed.

The other big challenge for Biden is that what should have been his strongest suit in the debate – foreign policy – is right now a subject Team Obama is desperate to avoid. Biden would want to tout his nearly two decades on the Senate Foreign Relations Committee and, as always, wave Usama bin Laden’s bloody tunic.

But Biden will take the stage tonight with Americans strongly believing that Team Obama has mishandled the deadly attack on the U.S. consulate in Benghazi, Libya. Worse for Biden, substantial points of fact remain unresolved. Rather than talking in generalities, Biden will have to answer pointed questions about the Libya mess.

The chances here of Biden making a serious misstep are high since the Obama administration itself has had multiple, conflicting accounts of what happened, why it happened and how it took so long to come clean on the nature of the attack.

Biden may benefit from the low expectations of the electorate, but if he comes out looking to show Democrats that he shares their rage, it will make him look defensive and nasty. He’d be better off to stay “Sheriff Joe” than trying to be a real gunslinger.

And Now, A Word From Charles

“I think if you look at the polls and a 16-point flip among independents towards Romney, you've got to say, as opposed to what Mara said, he has a foot in the door, a full leg, two arms, half a torso and a head.  That is my medical opinion, anyway.  He made incredible advances here.  It's up to Obama to reverse them.  I don't know if he can.”  


-- Charles Krauthammer on Special Report with Bret Baier”


Chris Stirewalt is digital politics editor for Fox News, and his POWER PLAY column appears Monday-Friday on FoxNews.com. Catch Chris Live online daily at 11:30amET  at  http:live.foxnews.com.