WATCH: Bernie Sanders Says His Fight Will Continue

Bernie Sanders said Thursday night that his major political task for the next five months is to "make sure that Donald Trump is defeated and defeated badly."

"I personally intend to begin my role in that process in a very short period of time," he said in an address to his supporters via livestream (full remarks as prepared for delivery here).

Sanders also said he looks forward to working with Hillary Clinton, his opponent who is now the Democratic Party's presumptive nominee, "to transform the Democratic Party" to better include issues important to working people and young people.

The remarks come two days after the last Democratic primary of the season was held in Washington D.C. Clinton won the district, adding to her already significant delegate and popular vote advantage.

In a turn from his usual campaign speech, Sanders also emphasized the importance of young people running for office at the state and local level to bolster the Democratic Party.

"Here is a cold, hard fact that must be addressed," Sanders said. "Since 2009, some 900 legislative seats have been lost to Republicans in state after state throughout this country. In fact, the Republican Party now controls 31 state legislatures and controls both the governors' mansions and statehouses in 23 states. That is unacceptable."

He called on the "thousands" of volunteers that helped his campaign to run for school boards, city councils, state legislators and governorships.

It's an unexpected overture to the Democratic Party, as he has been sharply critical of its national leadership, which it has accused of favoring Clinton's campaign from the start.

More expected, Sanders also spoke about many of his pillar campaign issues: income inequality, taking on Wall Street, combating climate change, making college more affordable and health care more accessible.

Sanders has said he will stay in the race until next month's Democratic convention, though there have been calls from some of his Senate colleagues and other Democratic leaders for him to bow out of the race.

And despite earlier vows to do so, the campaign now reportedly says it is not actively lobbying superdelegates to try and get them to switch their support from Clinton to Sanders. Campaign manager Jeff Weaver told Bloomberg Politics "With All Due Respect" the campaign has no plans in the near future to lobby them, either.

Sanders concluded by saying: "We have begun the long and arduous process of transforming America, a fight that will continue tomorrow, next week, next year and into the future."

"My hope is that when future historians look back and describe how our country moved forward into reversing the drift toward oligarchy, and created a government which represents all the people and not just the few, they will note that, to a significant degree, that effort began with the political revolution of 2016," he said.

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