Story highlights Bush has courted both Adelson and the Koch Brothers

Sanders also ridiculed Bush for saying Americans "need to work longer hours"

Arlington, Virginia (CNN) Democratic presidential candidate Bernie Sanders said Thursday that the $100 million raised by his Republican rival Jeb Bush was the latest ailment of what is "undermining the foundations of American democracy."

Taking several shots at Bush, who unveiled his record-setting haul just hours earlier, the Vermont Independent senator told a suburban crowd here outside of Washington that the sum was the latest signal that American democracy had failed. Sanders frequently criticizes the "billionaire class" and their influence in politics, but on Thursday he lumped Bush in with part of the problem.

"This money is clearly coming from the wealthiest people in this country," Sanders said, beginning his remarks by noting Bush's total. "The fact is that Bush's donors -- people like Sheldon Adelson and, most significantly, the Koch Brothers outfits, are now undermining the foundations of American democracy."

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Bush has courted both Adelson and the Koch Brothers, some of the Republican Party's most prolific financial backers, though neither is believed to have committed to supporting Bush.

Organizers emphasized that this event was a policy forum and not a campaign rally, and few in the crowd donned Sanders T-shirts or other paraphernalia. But the crowd was still very much his natural base, chanting, "Bernie! Bernie! Bernie!" over and over again as he entered and left the room.

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