Nicole Gaudiano

USA TODAY

WASHINGTON — Sen. Bernie Sanders said his 5-point win in Indiana's Democratic presidential primary on Tuesday will help him “pull off one of the great political upsets in the history of the United States.”

Sanders acknowledged that his path to the nomination is “narrow,” but he pledged to fight for every vote. He called on Clinton to debate him in delegate-rich California, where he said he will hold large rallies ahead of the state's primary in June. Sanders said he has enough money to fund a winning campaign for the remaining contests.

One problem for Sanders, though, is that only four of the remaining Democratic nominating contests are open or semi-open to independents, who largely favor Sanders. In Indiana's primary, which also was open, 72% of independent voters surveyed in a CNN exit poll said they supported Sanders.

Sanders says closed primaries deny energized independents the right to vote and discourage them from joining the Democratic Party.

“The world has changed,” he said earlier Tuesday on MSNBC. “More and more people are independents and I think it makes no sense for the Democrats to say to those people, ‘You can’t help us.’ For Democrats to do well in a national election, they’re going to need a lot of independents and I would not think it’s a good idea to push those people away.”

Sanders was responding to comments by Democratic National Committee Chairwoman Debbie Wasserman Schultz to Bloomberg Politics on Monday that a party’s nominee should be chosen by voters registered with that party.

57% of Democrats want Bernie Sanders to stay in the race, polling finds

Clinton has a nearly insurmountable lead in both pledged and unpledged superdelegates, the Democratic Party leaders and elected officials who can vote for the candidate of their choice at the party's national convention in July . But that hasn’t deterred Sanders or caused him to soften his criticisms of the former secretary of State.

At campaign rallies, he has continued highlighting Clinton’s donations from Wall Street and other special interests, and has called on Clinton to release transcripts of paid speeches she gave to Goldman Sachs and other corporations.

Sanders also told reporters Tuesday night he has “zero doubt” his campaign has been good for the Democratic Party and will result in higher turnout in November. Polls show a majority of Democrats want him to stay in the race.

Inside Clinton's plan to win over Sanders' backers and not lose the middle

Clinton has moved beyond the primary battle and is focusing her energy on defeating presumptive GOP nominee Donald Trump and winning the backing of Sanders’ supporters.

“I'm really focused on moving into the general election,” she told MSNBC on Tuesday. “And I think that's where we have to be, because we're going to have a tough campaign against a candidate who will literally say or do anything.”

Sanders needs to win 66% of remaining pledged delegates to secure a majority of those delegates. He also said that superdelegates committed to Clinton in states where Sanders won landslide victories should switch their allegiance to him. Key to that strategy is his argument that polls show he's better positioned than Clinton to defeat Trump. Sanders said after Trump won in Indiana that he doesn’t have the demeanor, policy background or ideas to become president.

“I would love to run against him, and I’m absolutely confident that not only we would beat him, but we’d beat him by a pretty large number,” he told reporters in Indiana.

Although Sanders' chances of winning the nomination still appear remote, any future delegates he wins will add to his influence at the Democratic convention. Last week, after losing four of five primaries, Sanders laid off more than 200 staffers and began talking about what will happen "if we do not win."

Sanders lays off hundreds of staffers as he weighs Plan B

Ilya Sheyman, executive director of MoveOn.org Political Action, said Sanders’ ideas are “the future of the Democratic Party.” To ensure victory in November, he said, Democrats need to embrace ideas such as a $15 minimum wage, debt-free college, a ban on fracking, and rejecting trade deals that he said devastate communities.

“With each victory, Sanders’ political revolution is forging a Democratic Party that is stronger and more engaged than ever before,” he said. “The movement that Bernie has ignited is continuing to catch fire.”

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