Democrats should not expect Joe Biden to get in the race. Democrats should want Joe Biden to get into the race.

That's my takeaway after watching the Democratic Party move leftward before my eyes for two-plus hours during Tuesday night's debate. Having lost one presidential primary to a candidate running to her left, Hillary Clinton clearly is determined she will never be out-progged again. But as she drifts leftward to fend off another primary challenger, this time from Sen. Bernie Sanders, she risks making it harder to win the general election.

It was always the general, not the primary, that lent a Biden candidacy any semblance of logic: The vice president could run a credible general-election campaign in the event Hillary's campaign melted down amid, say, the never-ending email scandal. But her fellow Democrats, starting with Sanders , declined Tuesday to make an issue of her inability to explain satisfactorily why she insisted on conducting sometimes-classified government business via a private account hosted on a home-brew server, or whether she'd risked national security by doing so, or whether the entire episode revealed something un-presidential about her character. They thereby gave her a pass on the only issue she can't effectively parry, making it harder to believe she won't be the Democrats' nominee.

But will she be a damaged nominee, and not only by the email story that has eroded public confidence in her honesty? That may depend on just how far off-center she stays until she has the nomination wrapped up. And by the end, Democrats may end up wishing Biden -- or someone capable of steering things back toward the middle -- had gotten in the race.

Tuesday night's debate was not a good omen for her on that count. When pressed by debate moderator Anderson Cooper on whether she is -- as she told a New Hampshire crowd in July -- a progressive, or -- as she told Ohioans last month -- a moderate, Hillary offered a bit of quintessentially Clintonian triangulation: "I'm a progressive who likes to get things done." From there, it was a series of similar back-and-forthing from her:

  • When asked about Sanders' apparent rejection of capitalism, Hillary offered about as strong as defense of it as you'll get from a Democrat these days: "(W)hen I think about capitalism, I think about all the small businesses that were started because we have the opportunity and the freedom in our country for people to do that and to make a good living for themselves and their families. ... we would be making a grave mistake to turn our backs on what built the greatest middle class in the history of the world."
  • When it came to gun control, though, she attacked Sanders -- who sports a D-minus rating from the NRA -- as being soft on the issue because he wouldn't hold gun manufacturers liable when one of their products is used to commit a murder.
  • When pressed on the repeal of banking regulations while her husband was president, Hillary, who has been paid millions of dollars to speak to Wall Street banks and taken in millions more in campaign donations from Wall Street, argued that she would be tougher on her benefactors than even Sanders (who called her "naive" for believing so).
  • When asked about her previous comments that she wouldn't make college "free" for the children of Donald Trump and other rich people, Clinton didn't defend her position so much as end up at the same place as Sanders: "My plan would enable anyone to go to a public college or university tuition free," she said, albeit with a vague provision requiring students to work 10 hours a week.
  • She dodged a potential controversy when, after being asked if she agreed with former Maryland Gov. Martin O'Malley that Obamacare should be expanded to cover illegal immigrants, Cooper suddenly gave her an opening to talk about running for office on her own right, and not because of her last name. (Though that was a strange moment, I thought Cooper otherwise did a fine job pressing candidates for answers on the issues.)
  • Hillary appeared to voice support for taxpayer funding of paid family leave, although her own plan calls for businesses to pick up the tab. During that answer, she made the bizarre claim that GOP efforts to cut government funding for Planned Parenthood somehow amounted to a GOP embrace of "big government."

Remember, this was about as close to the center as anyone on the stage, save former Sen. Jim Webb, got Tuesday night. We will have to leave it to future moderators to press Clinton (and the others) on how much all this would cost, and how she'd pay for it.

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But enough about Clinton. There were four others on the stage, weren't there?

That's not necessarily a rhetorical question. Webb often went long stretches without talking, about which he voiced his displeasure often. And we all would have been better off if Lincoln Chafee hadn't spoken as much as he did. (That includes Chafee's campaign.)

O'Malley was more of a presence on the stage than those two, but he doesn't have to merely rise from virtually non-existent to the mid-teens, as the more obscure Republicans contenders might in their much larger field. Both Clinton and Sanders are well above the highest point he'll ever reach, and nothing about Tuesday night will change that.

That leaves Sanders. If you liked him before, you're probably just as jazzed about the "political revolution" he called for. If not ... meh. I still do not believe even Democrats circa 2016 would nominate him, but his influence on the field -- read: Hillary -- is obvious. He is drawing the party toward him, not vice versa, and that will have real implications next fall. For all the talk about Trump's outsized effect on the GOP, Sanders is proving every bit as adept at pulling Democrats sharply in a direction that pleases one vocal segment of the base but will be a turn-off to most independent voters and even some of the party faithful.

With that, a parting question: Let's say the general election became a four-way race among Hillary, Bernie, Donald and _____ (Jeb, for argument's sake). Is Hillary or Jeb/other Republican more likely to win that one?