“Twenty-five percent of superdelegates are cronies, mostly. They weren’t elected,” Nader, an activist and former Green Party presidential candidate, told U.S. News in a story published Friday .

“They were there in order to stop somebody like Bernie Sanders, who would win by the vote.”

Clinton, the Democratic front-runner in the race for the White House, has secured 2,240 of the 2,383 delegates needed to clinch her party’s nomination, according to the Associated Press delegate tracker. That includes the backing of 524 superdelegates, the unbound powerbrokers who make their vote at the July convention. Sanders has tried to woo these votes to his sidel the Vermont senator has 1,473 delegates total, including just 40 superdelegates.

Sanders is vowing to fight until the Democratic National Convention in late July, citing his “momentum” from winning recent states. Still, Clinton has won some 3 million more votes than Sanders during the primaries.