Bernie Sanders has lit up the Democratic presidential race in a way that observers haven’t seen since, well, Barack Obama in 2008. He’s energized young people, brought blue-collar voters back to the party and changed the conversation about what’s wrong with America. For voters frustrated with the “system,” he’s changed the enemy from big government to “too-big-to-fail” Wall Street.

Were it not for the even more stunning rise of Donald Trump, in this election cycle, Sanders would be the big story.

Sanders has also had a great string of wins, lately, in the West and in Alaska and Hawaii, that have energized his supporters and donors. He’s even closed the gap in national polling among Democrats to a virtual tie with Clinton, and trimmed her elected delegate lead from 300 to about 200 (1239 -1028).

Sanders supporters are spending a lot of energy now railing against the super-delegate system, and they’ve got a point. Fifteen percent of all Democratic convention voters will be superdelegates — elected officials and party leaders — who will not be elected by the voters. It’s a system that, like the electoral college, was set up to protect systems and tradition against excessive passion by voters.

The Democrat’s superdelegate system is the product of the takeover of the party by George McGovern insurgents in 1972, when he went on to lose 49 states. From a democratic standpoint, it stinks. It favors insiders over new voices. And it favors old ideas over new ones, and pragmatism over ideals.

For Sanders supporters who are anxious about superdelegates tipping the scales, here’s the good news. Superdelegates are often aligned with the insiders they know, early on, but end up with whoever won the popular vote by the end of the process. See Obama in 2008, when Clinton started with a large lead among superdelegates. By the time the convention rolled around, they were all with Obama, simply because he won more delegates.

Sanders can win over the superdelegates — but only if he wins the most pledged delegates. To have any chance of doing that, he has to win over the next 10 days.

The Democratic nomination fight is now entering the decisive phase. As is to be expected, tempers are flaring, the language is getting coarser and people are saying things that they’ll avoid eye contact about later. Most of it will be forgotten, fortunately, by the last day of the summer’s convention. This is what happens.

Sanders supporters are also busy trying to promote a narrative in which Sanders wins. They all rely on his gaining increasing momentum until, at the convention, he tips the scales. All of it is possible, but is it plausible?

Let’s roll the numbers. About 40 percent of all delegates are still up for grabs, and 40 percent of those will be awarded, in six states, over the next 10 days. Sanders needs to win about 60 percent of all remaining pledged delegates to catch Clinton.

The first vote is in New York on Tuesday, and it’s the single most important. What happens in New York will create a domino effect in the nearby states that follow a week later, including Pennsylvania, Connecticut, Delaware, Maryland and Rhode Island.

Here are three challenges for Sanders over the next 10 days.

• Clinton is currently leading in all of those states by averaged margins of between 10 percent and 24 percent.

• These six states all hold “closed” primaries, meaning only Democrats can vote. Sanders has only won three of those, in New Hampshire, Vermont and Oklahoma.

• The six states have greater racial diversity than the northern tier and western states where Sanders has done best.

Can Sanders still win the nomination? Sure. But New York holds the key to his chances . If he can pull out a surprise win New York — or even a very close loss — he’ll raise a new round of doubts about Clinton’s viability and have a week of momentum and heightened interest to change the narrative and reshape of the race.

A win in New York would invariably tighten the polls in the surrounding states and add to his “comeback” momentum. This is how big changes happen in elections. It’s the Harry Truman effect.

If Sanders loses New York, though, he’ll be on the wrong side of that wave, Clinton will cement leads in the following week and the math will become impossible to overcome. In that scenario, in 10 days Clinton will effectively lock up the nomination.

Alan Caron, a Waterville native, is the owner of Caron Communications and the author of “Maine’s Next Economy” and “Reinventing Maine Government.” He can be reached at:

[email protected];