Let’s say that, on the morning of March 4, America wakes up to see that there are three candidates for the Democratic Party’s nomination who remain in serious contention. This is unlikely to happen in part because California’s votes won’t be fully counted until somewhere around Veterans Day, but for the sake of the thought experiment, let’s go with it.

So let’s say that the three candidates are Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (Mass.) and former New York mayor Mike Bloomberg. With 1,512 delegates allocated, Sanders has 630, Bloomberg has 490, and Warren has 392. Sanders, it seems, has a distinct advantage.

Except that the Democratic Party, being the Democratic Party, doesn’t make it that easy. At that point, there will be only 2,467 delegates still up for grabs, with 1,991 needed to clinch the nomination. In other words, Sanders would need to win 1,361 delegates, Bloomberg 1,501 and Warren 1,599. Or, put another way, Sanders needs to win 55 percent of the remaining delegates, Bloomberg 61 percent and Warren 65 percent.

In the abstract, winning 55 percent of delegates seems feasible. In practice, though, it means holding a majority in contest after contest where delegates are distributed proportionately. Sanders needs to stay above the 55 percent threshold in delegate wins in repeated contests where he’s facing off against two other contenders.

At least in our scenario. You can model your own using the tool below. The state of the race is set post-New Hampshire. The gray buttons pre-load existing polling averages calculated by RealClearPolitics. The polling data for states is all fairly old, but you can change the figures to whatever you want. Want to indicate that someone dropped out? Set their poll support to zero.

Each time you advance to a new contest (by clicking the yellow button), you’ll see the new delegates won next to the bar chart. It’s accompanied with the percentage of remaining delegates the candidate needs to win to clinch. If that percentage passes 100 percent — meaning there aren’t enough outstanding delegates to hit 1,991 — they’re eliminated.

Biden
Bloomberg
Buttigieg
Klobuchar
Sanders
Steyer
Warren
Other

Feb. 13

N.H.

24 delegates | 3,914 remaining

CandidateDelegatesAddedNeeded
Biden 6
0 1,985 50.7%
Bloomberg 0
0 1,991 50.9%
Buttigieg 23
9 1,968 50.3%
Klobuchar 7
6 1,984 50.7%
Sanders 21
9 1,970 50.3%
Steyer 0
0 1,991 50.9%
Warren 8
0 1,983 50.7%

You’ll notice that any candidate set to less than 15 percent support doesn’t earn delegates. That’s one of the party’s rules, as we explained earlier this week. It’s meant to make it easier for a candidate to build a majority of the delegates, since people getting 2 or 3 percent of the vote won’t be siphoning off delegates piecemeal.

You should also notice that, in most scenarios, it takes a while for a candidate to get a delegate majority and, therefore, the nomination. In some scenarios, no one may, meaning that the party gets to its convention without a clear nominee — the dreaded “contested convention” scenario.

What may be more subtle is how hard it is to overtake a front-runner. Once someone jumps out into the lead, it’s tough to catch them, because unless the challenger earns 85 percent of the vote in a contest, the front-runner gets delegates, too.

This isn’t meant as a prediction. It’s meant to demonstrate how the Democratic process relies on the slow accretion of delegates and presumes a relatively small field of viable candidates.

That may not happen in 2020. The tool above lets you see what happens if it doesn’t.