On the heels of landslide victories in Alaska, Hawaii, Idaho, Utah, and Washington, Bernie Sanders and his supporters are urging so-called "superdelegates"—Democratic party big-wigs who can support the candidate of their choosing on the convention floor—to join the revolution.

After his recent wins, Sanders trails rival Hillary Clinton by only 268 pledged delegates, according to the Associated Press tracker. Meanwhile, Clinton's lead among superdelegates is sizeable: she currently claims 469 to his 29.

"You've got superdelegates in states where we win by 40 or 50 points. I think their own constituents are going to say to them, 'Hey, why don't you support the people of our state and vote for Sanders?'"

—Senator Bernie Sanders

But, as ABC News pointed out, the elected officials and party elites who hold superdelegate posts "can swap their vote at any point until voting takes place at the party convention and will face grassroots pressure—and pressure from the campaign—to back the will of their hometown voters."

Indeed, Sanders said as much on CNN's "State of the Union" with Jake Tapper on Sunday.

"I think the momentum is with us," he said, following Saturday's three-state sweep. "A lot of these superdelegates may rethink their positions with Secretary Clinton."

Campaign press secretary Symone Sanders added in an interview on Monday: "You can't win like we won this past weekend and how we intend to continue to do well in these nominating contests and not expect superdelegates to take a second look. So we are focused on winning votes, winning the endorsement, if you will, of the American people. And we are hopeful and confident that those superdelegates will come along."

Furthermore, the Vermont senator noted, many of the roughly 700 superdelegates have yet to state their allegiance.

"I think when they begin to look at reality, and that is that we...are beating Donald Trump by much larger margins than Secretary Clinton," Sanders said on CNN. "And then you've got superdelegates in states where we win by 40 or 50 points. I think their own constituents are going to say to them, 'Hey, why don't you support the people of our state and vote for Sanders?'"

In Washington state, for example, where Sanders won close to 73 percent of the vote on Saturday, a majority of the 17 superdelegates have endorsed Clinton. A petition calling on those superdelegates to "Let the voters decide," and to support their constituents' wishes, has gathered close to 25,000 signatures as of Monday morning.

Alaska Democratic Party vice chairman Larry Murakami, who had previously donated to Sanders but formally had been uncommitted, told Politico on Monday that in the wake of Sanders' 82-18 trouncing of Clinton in his state on Saturday, he too was backing the democratic socialist.

"I'm going with Alaska," Murakami said. "I don't know that any other of the Alaska delegates have committed to one candidate or another, but I think it's totally appropriate if we're over 80 percent for one of us to step forward and say, 'yeah, I'm voting for Sanders like everyone in my district, like most of the people in my district and most of the people in Alaska'."

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And in Colorado on Easter Sunday, U.S. Rep. Jared Polis—a Democratic superdelegate who has publicly endorsed Clinton—received a handwritten note with a takeout order, encouraging him to cast his vote for Sanders, who won the Colorado caucus earlier this month. "The constituency has spoken," read the note from Native Foods Cafe in Boulder. "Use your power wisely. Feel the Bern. With the utmost respect, Native Foods. Happy Easter!"

Should Clinton lose superdelegate support due to a progressive challenger's momentum, it would not be the first time.

The Guardian reported in February 2008:

Hillary Clinton is starting to lose her overwhelming lead with super-delegates, the Democratic party officials whose votes she is counting on to help her close the gap with Barack Obama. Obama has received a steady flow of new backers in recent days while building a streak of 11 straight primary victories. [...] Most unnerving for Clinton is the trickle of super-delegates who have defected from her corner to Obama's. [...] Super-delegates who represent areas won by Obama are facing pressure to declare for him. One Clinton super-delegate, Texas congresswoman Sheila Jackson Lee, said colleagues had urged her to support Obama if he wins her district in the primary.

In the wake of Sanders' landslide victory last week in Idaho, superdelegate and Democratic National Committeeman Pete Gertonson announced in an email that he would be supporting the Vermont senator.

Gertonson wrote: "Pent-up frustrations of a red state, exploded Idaho Caucuses to historic numbers last Tuesday night, with 78% for Bernie Sanders! I'm proud to be an Idaho Democrat representing the people's choice. I'll cast our Super Delegate vote for Bernie Sanders!"

"I think what's important to remember here is that superdelegates are kind of like football recruits," Symone Sanders said Monday. "You know, they say they are coming but until they have signed on the dotted line and they're in practice, you don’t know that they're all the way with you and that they're on your team. And so we think that we still have time to garner support from these superdelegates, especially when we're winning."