(CNN) Former Democratic presidential nominee Hillary Clinton furthered her comments discrediting Sen. Bernie Sanders as a viable presidential candidate on Thursday, insinuating that his potential failure to "deliver the moon" would detract from efforts to rebuild public trust.

When asked by talk show host Ellen DeGeneres if she wanted to address her prior remarks about the Vermont independent, Clinton noted that while she originally made them about a year and a half ago, "I have a pretty clear perspective about what it's going to take to win, and as I said earlier, that's what I think the key calculation for any voter has to be."

"You've got to be responsible for what you say, and what you say you're going to do," Clinton added. "We need to rebuild trust in our fellow Americans and in our institutions, and if you promise the moon and you can't deliver the moon, then that's going to be one more indicator of how, you know, we just can't trust each other."

Sanders' campaign declined to comment Thursday. When Clinton's previous remarks surfaced last month, Sanders said in a statement that his focus was President Donald Trump: "Together, we are going to go forward and defeat the most dangerous president in American history."

Clinton's comments Thursday come as Sanders is in a near-tie with former South Bend, Indiana, Mayor Pete Buttigieg in the Iowa caucuses . As of Thursday afternoon, with 97% of precincts reporting, Buttigieg remained the leader of the race, with 26.2% of state delegates, while Sanders closely trailed with 26.1%.

Read More