Bernie Sanders may have an uphill battle to even approach Hillary Clinton’s delegate lead, but polls showing him as the Democratic Party’s strongest chance to take the White House in November could be his final argument in a race that will come down to superdelegates.

After a series of wins to end April that included a big victory in New York and the eastern seaboard states, Clinton has grown her delegate lead to nearly 300 over Bernie Sanders. With Clinton-friendly New Jersey still ahead and a chance to build on her lead, Sanders has shifted and is doing his best to make his case to superdelegates, the unpledged delegates who are free to choose the candidate they believe to be best to represent the party in November.

Clinton will likely be unable to secure the nomination on her own without superdelegates, and Sanders has been trying to push his own strengths in order to win them over.

He has some ammunition in the battle, including a series of polls that show him beating Donald Trump by wider margins and other polls showing Hillary Clinton’s lead of Trump slipping.

“The point that we’re going to make to the superdelegates is a very simple one,” Sanders told MSNBC’s Andrea Mitchell. “Over 400 superdelegates came on board Secretary Clinton’s campaign before anybody else was in the race, before anybody else was running. That’s pretty crazy. And that talks about the weakness of this whole superdelegate system.”

“No. 2, the point that we’re going to make loud and clear is that, in virtually every national poll that’s been out there in the last month or six weeks, and in almost every state poll, Bernie Sanders runs stronger against Donald Trump than does Hillary Clinton,” he continued. “And I think what every delegate to the Democratic National Convention wants, most importantly, is to defeat Donald Trump. The case we’ll make is that I am the stronger candidate.”

Other polls show some particular strengths for Bernie Sanders. A Gallup poll (via the Washington Times) found that he is viewed favorably by 55 percent of millennials, which the poll defined as Americans between the ages of 20 and 36. Only 38 percent had a favorable view of Clinton, and 22 percent said they had a favorable view of Trump.

His strengths also extend to the progressive wing of the Democratic Party. Among self-professed liberals in the younger age group, Sanders had a 78 percent favorable rating compared to 51 percent for Clinton.

While the poll numbers may not help Bernie Sanders win his primary battle against Hillary Clinton, they do show that he has tapped into the future of the party.

“Not only do millennials have favorable views of him personally, but there are also indications they are more likely than older generations to back his policies,” Gallup’s Jim Norman wrote.

“Sanders is expected to lose his fight for the Democratic nomination, but he seems to be succeeding at building a foundation for his progressive movement among the voters who will have the greatest say about the nation’s direction in the long run,” Norman added.

Many Democrats vote based on electability. Bernie Sanders is by far the most electable. pic.twitter.com/SlICeJj6R0 — My name is (@RevoltPolitic) May 13, 2016

.@BernieSanders rallies South Dakota voters: They have the money. We have the people. https://t.co/SBxPqupv8D — Morning Joe (@Morning_Joe) May 13, 2016

But in order to make his case, Bernie Sanders will likely need more than polls in his favor. With a handful of pledged delegates remaining, Sanders will need to win as much as he can in the last month in order to cut into Clinton’s lead and make the gap as small as possible. Otherwise, he will face the task of convincing nearly all superdelegates to leave their support of Clinton and come to his side.

[Photo by Bill Pugliano/Getty Images]