Bernie Sanders recently outlined a simple strategy for beating Clinton in the New York primary. The polls have him down by double digits there, and his campaign tends to do worse in closed primaries like New York’s. Does the Vermont senator have a chance?

In a recent speech in Syracuse, Sanders explained that the plan is simple — get the largest voter turnout in New York’s history.

“A week from today there’s going to be an enormously important Democratic primary in New York State. What we have found is we win when voter turnout is high, we lose when it is low. Next Tuesday, let us come out in large numbers. Let us have the highest voter turnout in Democratic primary history in New York.”

The polls show that Clinton is up by 13.8 percent, according to Real Clear Politics. If Bernie Sanders is going to secure another upset, he has to bring out enough people from groups that usually don’t bother to ruin the pollsters’ predictions.

Hillary Clinton calls New York her home state, but both candidates have roots there. Clinton served as the states senator, and Sanders was born in Brooklyn. [Photo by Andrew Theodorakis/Getty Images]

The perfect example of how this works is Michigan. On March 8th, Bernie Sanders won the state’s primary by a little over one percent, but the polls showed Clinton was ahead by double digits. (One of the last polls by Mitchell/Fox 2 showed Clinton up 27 points). Even Sanders was caught completely by surprise that night. The reason they were so wrong is because of turnout, according to the Washington Post.

Pollsters rely on past voter turnout to make a profile of what people will show up at the next contest. In Michigan, that wasn’t really possible. The state’s Democratic party attempted to move up its primary date to increase its relevance and political clout. The DNC punished the state, and candidates vowed not to actively campaign there.

As a result, only 600,000 voters turned up in 2008.

In 2016, it doubled to 1.2 million.

New York is very different. There were no anomalous circumstances in 2008, and about 1.9 million people voted. If Bernie Sanders wants to upset the pollsters like he did in Michigan, he’ll need to bring out over a million more people from under-represented groups — and there’s a big obstacle in the way.

Michigan was an open primary, meaning that voters not registered with the Democratic party could participate. New York is a closed primary, forcing Bernie Sanders’ independent supporters to register as Democrats to vote — that deadline already passed on March 25th.

The deadline is already a contentious issue, with frustrated voters on both sides of the aisle according to the Guardian. Recently, Eric and Ivanka Trump found out they would not be able to vote for their father because they had missed their chance. The two described the process to change party affiliation as “one of the most onerous” and emphasized the need to educate potential voters.

This years contentious election has exposed voters to numerous obstacles, from New Yorks closed primary deadline to a lack of polling locations in Arizona. [Photo by Mark Wilson/Getty Images]

The New York Post reports that 5,792,497 Democrats managed to register before the deadline. For Bernie Sanders to double voter turnout, like in Michigan, he needs roughly 65 percent of them to show up April 19th.

If Sanders succeeds, it will be a game changer. Closed primaries have proved to be a campaign weakness for the Vermont senator. So far, three other states have had similar closed primaries — Arizona, Louisiana, and Florida. Bernie has lost all three. He did win over “voters abroad,” who participate under the same rules.

Will Bernie Sanders get another major upset on April 19th? Independent voters will have to wait on the sidelines and hope for the best.

[Photo by Brett Carlsen/Getty Images]