Vermont Senator Bernie Sanders pushed back against Hillary Clinton’s criticism that he did not do enough on her behalf in the general election — claiming he had no control over his supporters who ultimately voted for Donald Trump.

“Let me just say this; I worked as hard as I could after endorsing Hillary Clinton. I went all over this country. And I would remind people, people say, ‘Not everyone who voted for Bernie ended up voting for Hillary.’ No kidding, thats what happens in politics,” Sanders told NBC News’ Chuck Todd on Meet the Press Sunday. “I worked as hard as I could to see that Hillary Clinton would be elected president.”

Sanders’ response comes nearly a week after Hillary Clinton, who defeated him in the Democratic primaries, released her memoir “What Happened,” chronicling her account of the 2016 election that resulted in her unexpected loss to President Donald Trump. Although Clinton defeated Sanders in the primary, he did not officially endorse her until July 2016, nearly a month after the last primary.

In her book, Clinton writes that Sanders’ attacks against her during the primary, particularly the ones where he stressed her reliance on donors from Wall Street, caused “lasting damage” and even served as an impetus for Trump to coin the term “crooked Hillary,” sentiments she has reiterated in a series of interviews last week. (Speaking on The View, she said she did not receive the same level of respect from Sanders and his supporters that she had given Barack Obama in 2008 after she lost the primary in terms of uniting the party).

Clinton also notes in her book that the Russians targeted Sanders supporters online as part of their purported effort to derail her campaign, putting fake news stories on message boards and Facebook groups in favor of Sanders.

Since the election, two surveys have emerged showing the percentage of voters in the Democratic primary who backed Sanders and then ultimately supported Trump could be as high as 12 percent, John Sides, a political science professor at George Washington University, wrote in the Washington Post last month. A CBS News analysis from 2008 found that 16 percent of voters who supported John McCain in that presidential election would have voted for Clinton had she been the party’s nominee instead of Barack Obama.

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Write to Alana Abramson at Alana.Abramson@time.com.