U.S. Democratic presidential candidate Bernie Sanders said he will meet with his rival Hillary Clinton Tuesday to press her to embrace his progressive agenda, saying he wants to know what she will stand for if she becomes president.

Speaking on ABC’s “This Week” program on Sunday, Sanders did not concede he had lost the Democratic presidential nomination to Clinton, who is leading in Democratic primaries and is the party’s presumed nominee.

Sanders said he and Clinton would discuss “if she wins, what kind of administration she will have.”

“What I need to see [is] a commitment that there will be progressive taxation,” he said, saying corporations and billionaires should pay higher tax rates.

He repeated his stance that he would do “everything I can” to ensure Donald Trump, the presumptive Republican nominee, will not become president.

Sanders said he wanted to see Clinton embrace his view that healthcare should be a universal right in America and public universities should offer education for free.

“Will she go as far as I would like her to go? No, she won’t,” he said. “But I think millions of people want to understand and see is what kind of commitment she has to addressing the real crises in the country.”

sanders Democratic U.S. presidential candidate Bernie Sanders gestures during a campaign rally in Cloverdale, California, June 3, 2016. Photo: Reuters/Stephen Lam