After Sen. Bernie Sanders’ (I-VT) campaign manager repeatedly argued Friday that Sanders could still win the Democratic nomination by flipping pledged superdelegates, MSNBC’s Thomas Roberts suggested that messaging to supporters was “intellectually dishonest.”

When Roberts pressed top aide Jeff Weaver about the campaign’s April fundraising reportedly being down by about 50 percent from strong showings in February and March, Weaver argued that Sanders being on the June 7 ballot in California would help down-ballot Democrats.

The MSNBC anchor interrupted: “But, Jeff—when we look at the math, is it intellectually dishonest to tell these supporters that you can actually win when there are only a little over 1,000 delegates left? Bernie Sanders needs to win almost 100 percent of them. Hillary Clinton only needs to win 10 percent of them before the convention.”

“I mean, there’s one thing to say you want to take it all the way to the end, but telling supporters that you can win is factually incorrect,” Roberts continued.

“No, that’s not true,” Weaver insisted. “Look, nobody is going to get to the convention with the number of pledged delegates they need to win. That’s just mathematically impossible for either candidate.”

He went on to say that superdelegates would decide the nominee, “that’s just a fact.”

Roberts pointed out that recent polls have found Sanders performs better than Clinton in a head-to-head general election matchup with presumptive GOP nominee Donald Trump, but said Sanders wouldn’t have that opportunity unless he could “flip” superdelegates committed to Clinton.

Weaver said that as primaries wind down and the Democratic National Convention approaches, the campaign would appeal to superdelegates who may have pledged their support to Clinton before getting to know Sanders and urge them to take another look at the Vermont senator.