The first day of the Democratic National Convention was a tumultuous one, as Bernie Sanders supporters repeatedly interrupted pro–Hillary Clinton speakers with boos and jeers.

But the final major speech of the evening was a sharply worded rebuttal to "Bernie or Bust" holdouts — delivered by none other than Bernie Sanders himself.

"Any objective observer will conclude that based on her ideas and her leadership, Hillary Clinton must become the next president of the United States," Sanders said. As the crowd cheered, he added, "The choice is not even close."

To back up this argument, Sanders made a straightforward, pragmatic case to his supporters that the issues are what matter most, and that the only way their preferred policies could be advanced is if a Democratic president — namely, Clinton — is elected.

And while the speech offered some praise of Clinton (he said she’d make "an outstanding president"), Sanders didn’t stop there. He also implied that he’d work to hold her to her promises once she did make it into office.

Sanders argued that nothing good would happen if his supporters stayed home this fall

Sanders began by reflecting on his campaign and its successes, citing his 8 million individual campaign contributions and 1,846 pledged delegates. But he quickly changed the subject.

This election, Sanders said, should not be about him personally. It’s really about "the needs of the American people," "ending the 40-year decline of our middle class," addressing "the reality that 47 million men, women, and children live in poverty," and "ending the grotesque level of income and wealth inequality that we currently experience." And it was about "which candidate understands the real problems facing this country and has offered real solutions."

For one, Sanders made the obvious "Supreme Court" argument, arguing that if his supporters stayed home and Trump were elected, he’d appoint terrible Supreme Court justices.

"If you don’t believe this election is important, if you think you can sit it out, take a moment to think about the Supreme Court justices that Donald Trump would nominate and what that would mean to civil liberties, equal rights, and the future of our country," Sanders said.

He also went on to praise Clinton’s positions as far preferable to Trump’s on issues like the minimum wage, health reform, climate change, and immigration reform — as well a new college affordability plan his campaign helped her craft.

But Sanders also suggested that he’d fight to hold Clinton to her promises once she got into office

Then, though, Sanders turned to praising the Democratic platform as a whole, which is a document that was produced not by Clinton herself but by negotiations between the Clinton and Sanders campaign. And that’s where things got interesting.

"I am happy to tell you," Sanders told his supporters, "that at the Democratic Platform Committee there was a significant coming together between the two campaigns, and we produced, by far, the most progressive platform in the history of the Democratic Party."

The platform, he said, calls for "breaking up the major financial institutions on Wall Street, "the passage of a 21st-century Glass-Steagall Act," and "strong opposition to job-killing free trade agreements like the Trans-Pacific Partnership." These are all issues Sanders — not Clinton — feels most passionately about. (Clinton does oppose the TPP now, but she took a notably long time to make that clear.)

He continued: "Our job now is to see that platform implemented by a Democratic Senate, a Democratic House, and a Hillary Clinton presidency – and I am going to do everything I can to make that happen."

It was a clever move, suggesting that the fight wouldn’t stop with electing Clinton. The true fight will continue when she’s in office — and even before she’s in office. (Notably, Sanders also ad-libbed a line that TPP must not get to the floor of Congress during the lame-duck session, meaning that he’d try to stop Democratic leaders from flip-flopping again on the issue.)

Sanders promised his supporters that he’d be there to continue waging that fight. But, he argued, the choice was clear. Electing Hillary Clinton is the best way to move America in the direction he thinks it should go.