Sanders, Fed Up With Increasing Attacks From Clinton, Publicly Responds.

Bernie Sanders scoffed at Hillary Clinton's claim that he didn't do as much to mobilize his supporters on her behalf as she did for Barack Obama in 2008.

"I worked as hard as I could to see that Hillary Clinton would be elected president," Sanders told NBC's Chuck Todd on "Meet the Press" on Sunday.

Clinton has expressed frustration in interviews promoting her new book, "What Happened," that she "didn't get that same respect and reciprocity" from Sanders that she showed toward Obama after losing a much more closely fought primary in 2008.

"The political sin he committed was the failure to move quickly to unify the party and his supporters," Clinton told CNN's Anderson Cooper last week.

But Sanders, who was Clinton's strongest rival for the Democratic presidential nomination, dismissed the idea that he could have persuaded any more of his supporters to swallow their disappointment and vote for Clinton.

"People say, 'Well, not everybody who voted for Bernie ended up voting for Hillary,'" Sanders said. "No kidding. That's what happens in politics. If my memory is correct, in 2008, something like 24 percent of the people who voted for Hillary Clinton in the primaries ended up voting for John McCain."

Clinton also dinged Sanders in her newly released book. "He certainly," she wrote of Sanders, "shared my horror at the thought of Donald Trump becoming President, and I appreciated that he campaigned for me in the general election. But he isn’t a Democrat — that’s not a smear, that’s what he says. He didn’t get into the race to make sure a Democrat won the White House, he got in to disrupt the Democratic Party.”