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WASHINGTON — Sen. Bernie Sanders on Sunday chalked up the fact that some of his supporters during 2016’s Democratic primaries eventually voted for Donald Trump in the general election to “the nature of politics.”

“People say not everybody who voted for Bernie ended up voting for Hillary, no kidding!" Sanders said on "Meet The Press."

He added, "That's what happens in politics," specifically pointing to some samples that have showed as many as a quarter of Clinton's primary voters in 2008 ended up voting for John McCain in the general election.

"That's the nature of politics," he said. "Most people, you know, are not rigidly Democrats or Republicans. They vote where they want. I worked as hard as I could to see that Hillary Clinton would be elected president."

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The Vermont senator was responding to criticism that Clinton leveled at him in her new book and in recent media appearances that he didn’t do enough to bring his supporters to her side after their contentious Democratic primary for president last year.

A recent survey of 50,000 people from the Cooperative Congressional Election Study estimated that as many as 12 percent of people who voted for Sanders in a primary ended up voting for Trump in the general.

"After endorsing Hillary Clinton, I went all over this country," Sanders said Sunday.

But he didn’t hold back from criticizing the Democratic Party. A long-time Independent, he did not indicate that he had any plans to run as a Democrat in Vermont’s Senate election next year.

"The current model of the Democratic Party obviously is not working," he said. "Republicans control the House, the Senate. They control the White House. They control two thirds of the governor's offices throughout this country. In my view Chuck, what we need to do is to reach out to independents."

Sanders on Sunday was also promoting his "Medicare For All" bill proposal that he unveiled this week. At least 15 Democrats have so far signed on to supporting it — signaling a fast shift among the Democratic ranks for a single-payer health care system.

"In my view, a Medicare for all, single-payer program will address those issues and guarantee health care to all people in a cost-effective way," Sanders said.

But he wasn't under any illusion that it will be passed any time soon under Republican control of Congress and the White House.

"It's not going to happen tomorrow," Sanders added. "I fully admit that. But we need to put the benchmark down there and go forward."