In the recent Democratic presidential debate, the person to watch was at home Biden his time.

After the debate, which had all the intensity and hostility of a suburban book club, media commentators wondered whether there is still room for Joe Biden to join the race.

Even if he decides to get in, it's not like he would make the field any more diverse. Looking at the stage in Las Vegas, I wondered if Democrats were trying to corner the market on white people over the age of 50. You know this is one bizarre election when Republicans have a lineup of presidential candidates that looks more like America.

Whether you think Biden should get into this race has a lot to do with how you feel about Hillary Clinton.

CNN seems to fancy the former secretary of state, and it will defend her. Just as, in the 2008 Democratic primary, it defended Barack Obama against Clinton's attacks. After last Tuesday's debate, the network's reporters, anchors and commentators ushered in the narrative that Biden should sit this one out.

Clinton has the Democratic nomination all wrapped up, they said. Democratic voters have enough choices already, they said. There is no room left for Joe, they said.

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On the contrary. The totally forgettable debate performances of Lincoln Chafee, Martin O'Malley and Jim Webb -- coupled with the valentine that Clinton got from Bernie Sanders, who told her that Americans are "sick and tired of hearing about your damn emails" -- suggest that Biden must get into this race.

The vice president needs to run for the good of the party. If the plan was for Democrats to give Clinton some sparring practice to toughen her up before the big fight, they are failing. After several months of campaigning, she still hasn't broken a sweat.

Biden can give Clinton a run for her money with Democratic voters who are looking for someone who is what she isn't -- authentic, trustworthy, likable, loyal to the White House. Biden is a steady and calming force in a campaign that has been chaotic, nasty and unpredictable. And he doesn't generate the personal scandals or drama that Clinton does.

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What Biden does seem to generate is fear among the Clintons. It doesn't matter that the Hillary-friendly media is so quick to dismiss the vice president. Because the Clintons won't. They'll go after him with the subtlety of an airstrike.

If Biden does indeed enter the race, it's not going to be easy for Clinton to launch a full-frontal assault on his record as vice president for the past two terms. This would mean attacking the administration in which she once served.

And that would expose a rift that neither Democrats nor their surrogates in the media want to reveal. It's been clear for some time that President Obama and those loyal to him, such as White House adviser Valerie Jarrett, have no desire to see Clinton succeed Obama and that they would much prefer Biden. The best way to ensure a "third term" for this president is to elect the vice president.

So the safest path for the Clintons to take to destroy Biden would be to reach all the way back to his long career in the Senate. We'd surely hear about how he allowed Anita Hill to be treated during the Clarence Thomas hearings makes him a sexist, and how his efforts to put more cops on the street makes him a racist. It would get ugly.

Ironically, the same asset that helped make Biden an attractive pick as Obama's running mate -- namely his appeal to white men in the working-class "lunch bucket" demographic -- could soon become a liability. It used to be considered a good thing that Biden understood the concerns of blue collar white men. The Clintons will paint it as a sign that Biden is out of touch with a country that is increasingly diverse.

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Already we've seen it reported that it was Biden who leaked the story to New York Times columnist Maureen Dowd about how his dying son, Beau, asked him to run for president. Dowd's column in effect helped fuel speculation that Biden was running and made him appear sympathetic. But the revelation that he might have been the source of the leak struck some Democrats as craven and opportunistic. Someone spilled those beans -- to smear Biden.

How low will a politician sink to defeat a rival? Keep an eye on the Clinton camp. We may be about to find out.