Many Democrats are now understandably fixated on the strong showings of former Mayor Pete Buttigieg and Sen. Bernie Sanders, or on the disappointing performances of former Vice President Joe Biden and Sen. Elizabeth Warren. But the most important new dynamic in the race comes from Michael Bloomberg, a candidate who wasn’t even on the ballots or stages in Iowa and New Hampshire.

Ultra-sensitive to criticism that his entry into the race and more than $300 million in spending (so far) might splinter the centrist Democratic vote and lead to a Sanders nomination or a brokered convention, Bloomberg made the stunning promise last month that he would spend up to $1 billion in the general election campaign against Trump no matter who the Democratic nominee ends up being.

This massively important decision, if in fact fulfilled, will give the eventual Democratic nominee a much better chance to compete against Trump’s well-funded social media campaign, as well as helping Democratic candidates all the way down the ballot.

Yet in practice, Bloomberg’s own continued candidacy, according to the RealClearPolitics average of national polls, is further splitting the crowded moderate vote -- made up of Biden, Buttigieg, Amy Klobuchar and Bloomberg -- while Sanders continues to solidify the suddenly less crowded left with only the badly fading Warren competing for that wing of the primary voters.

Bloomberg, even after the largest campaign ad buy in primary history, is polling at less than 15% nationally, still behind Biden, and seems to be simply hurting Biden, Buttigieg and Klobuchar, but not Sanders.

Right now, the prognosticators at FiveThirtyEight have Sanders as the odds-on favorite, with a one in three chance to win the nomination.

But the chances that no candidate gains a majority of delegates before the convention, as I first warned about almost a year ago, are now higher than ever, with FiveThirtyEight saying there is a 33% chance of no candidate having a majority before Milwaukee.

Yet this is likely to merely help Sanders since in a Democratic Party obsessed with plurality-based fairness, it will be very difficult to deny the candidate with the most delegates the nomination, as happened in previous eras, meaning whoever has the largest number of delegates will be nearly guaranteed the nomination. In this sense, the term "brokered convention" many have been using is entirely misleading -- it is hard to imagine any scenarios or backroom deals that would, say, deny Sanders the nomination, without tearing apart the Democratic Party’s left and moderate wings and guaranteeing Trump's re-election.

Expecting any mainstream candidate to leave before Super Tuesday, March 3, is unrealistic -- although Tom Steyer, Tulsi Gabbard and others who have zero chance should be pressured to do so now.

But immediately after Super Tuesday, party leaders should exert pressure so that the centrist candidate with the most delegates is the only one who stays in the race. This means that at least two, and more likely three, of the center four -- Biden, Buttigieg, Bloomberg, and Klobuchar -- who have the fewest delegates must get out. The goal must be a single centrist candidate against Sanders as quickly as possible.

Today, Bloomberg’s chances at the nomination are about 1 in 30, according to FiveThirtyEight, but the same standard should apply to Biden (currently 1 in 6 chance), Buttigieg (1 in 20), and Klobuchar, who lacks a nation campaign infrastructure and has even less chance (although she may be angling for VP).

The tempting calculus for these candidates is to stay in the race as long as possible in order to play powerbroker at a fractured convention in Milwaukee. This must be avoided at all costs, as it is likely to play into the hands of Sanders.

Recently, even leading progressive thinker Ezra Klein explained the danger of a far left candidate like Sanders for Democrats in his essay in the New York Times, “Why Democrats Still Have to Appeal to the Center, But Republicans Don’t”.

Yet, Bloomberg's and Buttigieg’s weakness with black voters continues to be a major problem for both campaigns, and seems to be Biden’s last hope, as he has made so blatantly clear at his South Carolina rallies. New revelations about Bloomberg’s remarks in 2015 about his stop-and-frisk policy may further complicate his insurgent effort.

Still, given Biden’s sudden collapse and various problems with the Buttigieg and Klobuchar campaigns, Bloomberg’s unprecedented spending may yet leave him the field one-on-one against Sanders, in a race of the billionaire moderate against the anti-plutocratic socialist.

Perhaps nearly as interesting will be the sincerity of Bloomberg’s pledge to help any Democratic nominee, which will be severely tested if Sanders is the nominee -- showing there may be limits to even Mayor Mike’s largess in his desire to beat Trump. In that event, it may be that Bloomberg would use much of his money to protect down-ballot candidates.

Like it or not, under any scenario, Bloomberg’s billions give him a unique role in the Democratic nomination and the general election, as well. Let’s hope he uses them wisely.