(CNN) On the eve of the South Carolina primary -- the fourth vote of the 2020 Democratic presidential race -- the dynamic of the contest is now crystal clear: There is Bernie Sanders , and then there are all the other candidates competing to be the alternative option to the Vermont senator.

Sanders' wins in New Hampshire and Nevada , coupled with his near-victory in Iowa , have showcased not only the durability of his core support but also his ability to grow his backing in key Democratic constituencies. (Sanders won a whopping 53% of the Hispanic vote in Nevada.)

He is now surprisingly competitive with longtime leader former Vice President Joe Biden in South Carolina, and polling in big states set to vote on Super Tuesday like California and Texas suggests Sanders is likely to emerge on March 4 with a very clear delegate lead over the rest of the field.

The race to be the Sanders alternative (or the anti-Sanders) is far less formed. If Biden can win in South Carolina -- and even better if he can do so by a wide margin -- he will have a case to make that he is the Sanders alternative given his support in the black community. (Biden told the Charleston Post & Courier on Thursday that candidates who can't get a significant chunk of black voters should leave the race.) A Biden victory, especially if it's by double-digits, would seemingly position him well heading into Super Tuesday.

Former South Bend, Indiana, Mayor Pete Buttigieg has, to date, made the most pointed argument against Sanders -- suggesting that nominating a democratic socialist will have a lasting and deleterious impact on the broader Democratic Party. Former New York City Mayor Michael Bloomberg has been less effective as an anti-Sanders messenger, but he is worth $60+ billion and will continue to spend heavily to convince voters he is the only viable option.

And then there is Elizabeth Warren . While Warren, like everyone else in the race, is governed by the Bernie/Not Bernie dynamic, the Massachusetts senator seems unwilling to acknowledge that fact -- spending most of her rhetorical fire on Bloomberg rather than Bernie in Tuesday's debate in South Carolina. If Warren has a plan on how she gets to the nomination without drawing hard comparisons to Sanders, we're all ears.

Below, the five candidates most likely to wind up as the Democratic nominee against President Donald Trump

5. Elizabeth Warren: If we're being real with ourselves, the senior senator of Massachusetts' shot is declining, not rising. Still, Warren has a better shot than Minnesota Sen. Amy Klobuchar. Warren's national poll standing is : If we're being real with ourselves, the senior senator of Massachusetts' shot is declining, not rising. Still, Warren has a better shot than Minnesota Sen. Amy Klobuchar. Warren's national poll standing is holding in the low teens , which should be enough to win some delegates on Super Tuesday. Furthermore, Warren has found that attacking Bloomberg has allowed her to fund her campaign . But just to show you Warren's deep hole: she may get beaten by Sanders in her home state. (Previous ranking: Not ranked)

4. Michael Bloomberg: Sometimes things in the abstract are better than things in reality. Welcome to the Bloomberg campaign for president. After spending hundreds of millions of dollars on advertisements, the former mayor of New York saw his numbers climb nationally and in some Super Tuesday states. : Sometimes things in the abstract are better than things in reality. Welcome to the Bloomberg campaign for president. After spending hundreds of millions of dollars on advertisements, the former mayor of New York saw his numbers climb nationally and in some Super Tuesday states. Then Bloomberg stepped onto the debate stage, looked not so good (to put it mildly) and hit a wall. Bloomberg's polling has stagnated. Worse for him, the potential comeback story of Biden limits his appeal as the electable moderate. (Previous ranking: 4)

3. Pete Buttigieg: Buttigieg had to be hoping for more in Nevada. His third-place finish was respectable but did nothing to quiet critics who say he can't win non-white voters. That storyline is likely to get even more fuel on Saturday -- as there is : Buttigieg had to be hoping for more in Nevada. His third-place finish was respectable but did nothing to quiet critics who say he can't win non-white voters. That storyline is likely to get even more fuel on Saturday -- as there is little evidence to suggest that the former South Bend mayor is going to surprise in South Carolina. And then comes Super Tuesday, where better-known candidates like Sanders, Bloomberg, Biden and even Warren may well do better. That said, Buttigieg has finished first, second and third in the first three votes -- a record that only Sanders can top. And that demonstrated appeal to voters means we shouldn't count him out. (Previous ranking: 2)

2. Joe Biden: The former vice president needs a win in South Carolina to continue on in this race, and it looks like he could get it. A : The former vice president needs a win in South Carolina to continue on in this race, and it looks like he could get it. A Monmouth University poll released Thursday has Biden up 20 points. Biden still has a lot of flaws (such as a lack o f money and organization ). But a big win in South Carolina could be what Biden needs heading into Super Tuesday. Back in 2008, then-Sen. Barack Obama got a 10-point bounce in the national polls after winning in South Carolina. That just happens to be about the difference nationally between Biden and Sanders right now. (Previous ranking: 3)

1. Bernie Sanders: Two weeks ago, we had Sanders in this top slot but there were arguments to be made that he was a weak No. 1. He had lost the delegate count in Iowa to Buttigieg and prevailed in New Hampshire by less than was expected. But then came the Nevada caucuses six days ago. Sanders' victory there was complete -- winning across demographic groups, age groups and ideological groups. It still seems unlikely that Sanders will wrap the nomination up anytime soon, but he has the best odds of anyone in the field of doing so. (Previous ranking: 1)