Bernie Sanders upset Hillary Clinton in Indiana's Democratic primary Tuesday night, giving his flagging campaign another reason to carry on to Philadelphia even though he has virtually no chance of overtaking Clinton for the nomination.

With more than three-quarters of precincts reporting, Sanders led 53 percent to 47 percent.


Less than a half hour after results began pouring in, Sanders rallied supporters in Louisville, Kentucky, where voters will head to the polls on May 17. Ticking through his standard stump lines while bashing Clinton for her paid speeches and 2002 vote in favor of invading Iraq, Sanders told a boisterous crowd that their ideas will prevail.

“I’ll tell you what is extremely exciting for me, and that is that in primary after primary, caucus after caucus, we end up winning the vote of people 45 years of age and younger,” Sanders said. “And that is important because it tells me that ideas that we are fighting for are the ideas for the future of America and the future of the Democratic Party.”

Clinton was not expected to deliver any remarks on Tuesday night. Her campaign announced she will speak in Washington Wednesday at a reception organized by the Asian Pacific American Institute for Congressional Studies.

The win bolstered Sanders' pledge to remain in the race through the Democratic National Convention in Philadelphia despite trailing in the overall and pledged delegate counts. Because Indiana allocates delegates proportionally, though, it will produce more of a psychic boost for Sanders and his supporters than an actual dent in Clinton's lead.

The calendar for the rest of May portends favorably for Sanders, as well, with West Virginia up next on May 10, followed by Kentucky and Oregon on May 17.

“I want to thank the people of Indiana for the great upset victory that they gave us tonight. This is the 18th state that we have won, and we expect more victories in the weeks to come," Sanders said in a statement released Tuesday night.

Sanders is favored to win those three contests, though none has a purely open primary, like in Indiana. Sanders has performed better in states where voters can vote in whichever party's primary they prefer, regardless of registration.

After dominating the recent slate of Democratic primaries and extending her already daunting lead over Sanders, Clinton made clear again ahead of Tuesday night's returns that she's already moved on from the primary campaign and is focusing on Donald Trump in November.

"I think we had a good campaign, we ran hard. But, you know, I'm really focused on moving into the general election," Clinton said in an interview Tuesday with MSNBC's "Andrea Mitchell Reports." "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. And we're going to take him on at every turn on what's really important to the people of our country."

With 83 pledged delegates at stake, Indiana loomed large as an opportunity for Sanders to pull an upset in a state where Clinton has led narrowly in most recent polls. An NBC News/Wall Street Journal/Marist survey conducted last week showed her with a 4-point lead.

Sanders had kept up his criticism of the Democratic nomination process, riffing to crowds across Indiana on Monday about the outsize role superdelegates play and vowing to fight for a contested nomination should Clinton need those superdelegates to put her over the magic number of 2,383 to clinch.

Clinton entered the night with 1,645 pledged delegates to Sanders' 1,318; among superdelegates, she has a staggering, 520-to-39 advantage.

"I have a whole lot of problems with the nature of superdelegates right now and the power that they have," Sanders remarked Tuesday morning to MSNBC in Indianapolis, before jetting to Louisville, Kentucky, to rally supporters later in the evening. "I mean, the truth is, you've got over 700 superdelegates, and that is too many, I think. So I think that's something we have to rethink."

Sanders has had the look of a man struggling to come to terms with his almost nonexistent chance of wresting the nomination from Clinton.

In the wake of his recent string of losses, in one breath his campaign said it was in reassessment mode, shedding campaign staff and hinting strongly that the endgame is to yank the Democratic platform to the left; in the next, the candidate was blasting Clinton and talking about a contested convention in Philadelphia, as if nothing had changed.

On Tuesday, however, he vowed to keep up the fight, and said his ongoing struggle with Clinton would help the party in the fall.

“The Clinton campaign thinks this is over. They’re wrong,” Sanders said in the statement. "Maybe it’s over for the insiders and the party establishment, but the voters in Indiana had a different idea. The campaign wasn’t over for them. It isn’t over for the voters in West Virginia. It isn’t over for Democrats in Oregon, New Jersey and Kentucky. It isn’t over for voters in California and all the other states with contests still to come."

Clinton backers are exasperated by Sanders’ refusal to bow to what they call political reality but are treating him gently because he'll be critical to the task of uniting the party for the general election. The frustration is all the more palpable with Trump saying that Sanders’ harsh criticisms will be a gift to the billionaire in a matchup with Clinton.

The Clinton campaign turned its attention away from Indiana in the days immediately preceding the contest, seeking to tamp down expectations in a state where Clinton has led in the polls but only narrowly defeated then-Illinois Sen. Barack Obama in the 2008 primary.

While Sanders barnstormed through Fort Wayne, Evansville and Indianapolis on Monday, Clinton set out on a two-day van tour of Appalachia, visiting West Virginia and Kentucky, which will vote on May 10 and May 17, respectively. She also went to Ohio, where she addressed jobs and manufacturing.

During that swing, Clinton was confronted in coal country over comments she made in March in which she vowed to "put a lot of coal miners and coal companies out of business.”

Though Clinton had followed up by saying she would make sure those who lost work would not be forgotten, the former secretary of state was confronted by a man in West Virginia on Monday evening.

"I'm not writing off any part of America, any people in our country, and that includes here in West Virginia, in coal country," she said Tuesday on MSNBC.