WASHINGTON (AP) — Bernie Sanders acknowledged Sunday that his "uphill climb" to the Democratic nomination depends on winning over superdelegates, the elected officials, lobbyists and other party insiders who are free to back either candidate.
He's asking those party leaders, who overwhelmingly support rival Hillary Clinton, to "go into their hearts" and change their support to Sanders.
It's an admission that even some of his own aides call ironic, given that Sanders has focused his campaign on taking down what he calls a corrupt political establishment. The Vermont senator formally joined the Democratic Party a year ago, after serving decades in Congress as a self-identified democratic socialist.
In a press conference organized to mark the year anniversary of his insurgent bid, Sanders called on superdelegates to reflect the vote in their state. He also cast himself as more electable against Donald Trump, arguing that superdelegates should prioritize beating the GOP frontrunner over other concerns.
"It's a steep hill to climb," he admitted, at a press conference in Washington on Sunday. "But, at the end of the day the responsibility that superdelegates have is to decide what is best for the country and what is best for the Democratic Party."
To win the nomination, Sanders would have to flip hundreds of superdelegates, far more than the several dozens that changed from Clinton to support then Illinois Sen. Barack Obama eight years ago. Sanders would also have to convince superdelegates to vote against the national pledged delegate leader — an unprecedented political maneuver.
Though they've been part of Democratic presidential elections since 1984, the superdelegates have never been a determining factor for the nomination because they've never overturned the candidate that leads nationally in pledged delegates.
Hillary Clinton is 91 percent of the way to clinching the Democratic nomination, when including superdelegates. She leads in both pledged delegates by 1,645 to Sanders' 1,318, according to the Associated Press. It takes 2,383 to win.
Sanders would need to win more than 82 percent of the remaining delegates and uncommitted superdelegates through June if he hopes to clinch the nomination; currently, Sanders has been winning just 39 percent.
So far, no Clinton-backing superdelegates have flipped to Sanders, despite an aggressive lobbying campaign from his supporters that in some cases included harassing phones calls and online threats.
Despite her lead, Sanders says he plans to compete through the remainder of the primary contests in May and June. The question is whether he'll have the resources to fund an aggressive advertising campaign, particularly in the expensive media markets of California.
Sanders said on Sunday that he brought in about $26 million in April for his campaign, a steep decline from the $46 million he raised in March.
Earlier this week that he was laying off hundreds of staffers after losses last month in New York and several East coast primaries. The campaign said it was downsizing its staff because about 80 percent of the primaries and caucuses had been completed and the changes would allow it to focus heavily on California.
Sanders' campaign did not report Sunday how much it spent in April or how much it had in the bank at the end of the month. The figures will be included in fundraising reports filed with the Federal Election Commission later in the month.
Clinton's campaign did not immediately report its fundraising totals in April. The former secretary of state entered April with $29 million in the bank compared to $17 million for Sanders.
Sanders has vowed to campaign into the party's convention in Philadelphia in July and seek as many delegates as possible to influence the party's platform.
"We also can do arithmetic. We understand her advantage is substantial," said senior adviser Tad Devine. "We want to be as strong as possible going in there. But right now the goal is victory."
Associated Press writer Hope Yen contributed to this report.
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