After three big wins out west, Democratic presidential hopeful Bernie SandersBernard (Bernie) SandersSanders thanks Iowa voters for giving momentum to progressive agenda Live coverage: Gillum clashes with DeSantis in Florida debate Miami Herald endorses Gillum for governor MORE said he thinks many of the party's superdelegates who have pledged to rival Hillary ClintonHillary Diane Rodham ClintonSanders thanks Iowa voters for giving momentum to progressive agenda Manchin wrestles with progressive backlash in West Virginia Arizona newspaper backs Democrat in dead heat Senate race MORE will switch to his side.

ADVERTISEMENT

"I think the momentum is with us," Sanders said on CNN's "State of the Union" with Jake Tapper on Sunday. "A lot of these superdelegates may rethink their positions with Secretary Clinton."

The Vermont senator swept Saturday's Democratic contests in Washington, Alaska and Hawaii, easily winning the majority of the 142 pledged delegates in those states. The biggest prize of the day was in Washington, which offered 101 delegates to be split up on a proportional basis.

The latest delegate counts still put Sanders behind Clinton, however, with 975 pledged delegates to her 1,243.

In addition, 469 superdelegates back Clinton, while only 29 support Sanders.

Sanders on Sunday said those superdelegates may begin to see the "reality" that he's the best candidate to beat GOP front runner Donald TrumpDonald John TrumpFive takeaways from Gillum and DeSantis’s first debate GOP warns economy will tank if Dems win Gorbachev calls Trump's withdrawal from arms treaty 'a mistake' MORE.

"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. "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?'"

This report was updated at 9:31 a.m.