Updated 12:53 PM ET, Sun May 17, 2015
Washington (CNN)-Democratic presidential contender Bernie Sanders is portraying his rival Hillary Clinton a newcomer to the left's fight against income inequality.
"It's one thing to talk about it. It's one thing to act on it," the Vermont senator said during an interview with CNN's Brianna Keilar aired Sunday on "State of the Union."
"You are looking at the most progressive member of the United States Senate," he said, touting his relationship as a "good friend" of firebrand Massachusetts Sen. Elizabeth Warren.
Sanders said he's led efforts to challenge Wall Street, push for universal health care, tackle climate change and combat "disastrous trade agreements."
He also said Clinton should take a position on the Trans-Pacific Partnership, a massive 12-country deal that President Barack Obama is pushing to the dismay of liberals.
"You can't be on the fence of this one," he said. "You're either for it or you're against it. No fence-sitting on this one."
Sanders said he personally likes Clinton. He said he's willing to challenge her on policy issues -- but that he hopes media will cover those differences without Sanders having to launch "reckless attacks."
"Are you in the media prepared to allow us to engage in that serious debate?" he said. "Or do I have to get media attention by simply making reckless attacks on Hillary Clinton or anybody else? I don't believe in that. I believe in serious debates on serious issues."
'I too am curious where Hillary stands on TPP, I am all for Bernie as I think, as he says 'It's time to talk about the Issues' and more that have to do with the 'People' and not 'Corporations'!!!'