That last fact is a huge point of contention between the two camps right now, with Hillary supporters—full disclosure: I proudly voted for Hillary here in North Carolina—all but certain that the former Secretary of State will win the right to run against whatever goat rodeo the Republicans set loose this summer. Bernie supporters look at a mostly blank map and see more than half the races left, giving Bernie what they say is a solid path to the nomination.

I know plenty of people who are tired of hearing about the much-vaunted “delegate math,” but just like electoral votes are what elect a president (until we amend the Constitution otherwise), delegates are the deciding factor in a primary cycle.

That delegate math is pretty ugly if you want Bernie Sanders to be the next Democratic nominee.

Hillary’s pledged delegate lead has steadily grown since she won the Nevada caucuses on February 20, 2016.

The grave mistake the Bernie campaign made at the beginning of this cycle was essentially writing off the south, an error that allowed Hillary to run up enormous margins in delegate-rich states like Georgia and Texas while scoring a blend of small wins and solid losses in other states with smaller delegations. This discrepancy has allowed Hillary to amass a significant lead in pledged delegates, earning 776 to Bernie’s 551 through Saturday’s caucus in the Northern Mariana Islands.

A 225-delegate lead doesn’t seem like much, but the Democratic Party allocates pledged delegates proportional to the vote received. This theoretically helps non-front runners accrue delegates despite falling behind in the vote, but it winds up hurting them more than it helps. This proportionality cements even a small delegate deficit, sometimes growing so large that it requires the runner-up to achieve landslide wins to catch up. Build up enough of a deficit and that’s the ball game. That’s how Obama edged out Hillary in 2008.

We’re heading into what is arguably the most favorable stretch of the primary calendar for Bernie Sanders, who has performed exceedingly well in smaller and more liberal caucus states. This advantage is exemplified by his decisive wins in Colorado and Minnesota on Super Tuesday, where he finished ahead of Hillary by about 20 points in each case. It’s not a stretch of the imagination to figure that he could win almost every contest after March 15 until New York votes on April 19.

However, while the optics of winning state after state looks great for fundraising and morale-building, the delegates are what matters, and the current trajectory is not kind to Bernie.

In order for Bernie to catch up with Hillary, here’s an example of the kind of margins by which he needs to win the remaining 34 races in order to virtually tie with Hillary: