You don’t have to look far for disappointed reactions to Bernie Sanders' sweeping endorsement of Hillary Clinton on Tuesday, despite saying that he wanted “to make it as clear as possible as to why I am endorsing Hillary Clinton and why she must become our next president.”

But beyond the cries of “nope” or worse on social media, including some claiming he has become a traitor to the revolution to transform America that he inspired, there was something intriguing and perhaps unprecedented in Sanders’ speech and his follow-up e-mail to supporters.

In the speech, Sanders did not just say Clinton agreed with him on many key issues and moved toward him on other issues, such as raising the minimum wage, creating jobs by rebuilding infrastructure, appointing Supreme Court justices who will overturn Citizens United and uphold the rights of minorities and immigrants, adding a public option under Obamacare, opening Medicare to those 55 and older, cutting prescription drug costs, making public colleges and universities tuition-free, lowering student loan debt, reforming the criminal justice system and holding Wall St. accountable.

Sanders went further; he said that the revolution would continue and he would not disappear from the national stage, but would keep campaigning for progressive ideas and candidates.

“I am happy to tell you that at the Democratic Platform Committee which ended Sunday night in Orlando, 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,” he said. “Our job is now to see that platform implemented by a democratically controlled Senate… a democratically controlled House… and a Hillary presidency… And I intend to be in every corner of this country to make certain that happens.”

Time will tell if there indeed is a serious and lasting realignment of the Democratic Party toward the progressive left, as Sanders and Clinton both professed Tuesday. Sanders amplified his pledge to keep campaigning in an e-mail to supporters, saying, “We cannot let all of the momentum we have achieved in the fight to transform America be lost.”

“In the coming weeks, I will be announcing the creation of successor organizations to carry on the struggle that we have been a part of these past 15 months,” he said. “Our goal will be to advance the progressive agenda that we believe in and to elect like-minded candidates at the federal, state and local levels who are committed to accomplishing our goals.”

Sanders also said in that e-mail—but not in New Hampshire with Clinton—that his effort to transform the Democratic Party’s nominating process by eliminating the superdelegate system wasn’t over.

“We still have a tremendous amount of work left to do,” he said. “We have to enact the kinds of reforms to the Democratic Party and to the electoral process that will provide us the tools to elect progressive candidates, to allow new voices and new energy into the Party, and to break up the excessive power that the economic and political elites in the Party currently have.”

But most intriguingly, Sanders, who has refused to follow the well-worn path of defeated presidential candidates grudgingly returning to their day jobs after losing, said he would keep moving ahead and focusing on the political present and future.

“You should know that I intend to be actively campaigning throughout this election season to elect candidates who will stand by our agenda,” he reiterated. “I hope to see many of you at events from coast to coast.”

It’s easy to dismiss Sanders’ pledge to keep campaigning. Every step of the way the pundits and political professionals have underestimated him. Even his refusal to drop out of the race after the June 7 defeats in the big state primaries in California and New Jersey raised many eyebrows. But as Alex Sietz-Wald noted for NBCNews.com, Sanders' determination to plow ahead resulted in the Democratic Party platform committee adopting 80 percent of what the Sanders campaign demanded. Who knows what they will achieve when pushing the party’s Rules Committee on superdelegate reform.

Some of Sanders’ ongoing success appears to be the tacit acknowledgment by the Clinton campaign that they need Sanders—and his connection to a grassroots movement that holds him nearer and dearer to their political hearts than the party’s nominee.

Clinton's remarks on Tuesday even suggested that was the case.

“Throughout this campaign Senator Sanders has brought people off the sidelines and into the political process. He has energized and inspired a generation of young people who care deeply about our country, and are building a movement that is bigger than one candidate or one campaign,” she said. “So thank you, thank you, Bernie, for your endorsement, but more than that, thank you for your lifetime of fighting injustice. I am proud to be fighting alongside you, because my friends, this is a time for all of us to stand together.”

Americans will soon see how they stand together in coming weeks—whether it is the face of a newer and more progressive Democratic Party or a fraught alliance of political necessity. And Sanders supporters who found themselves cringing Tuesday will also likely reexamine their assessment of voting for Clinton when they see just what Donald Trump and the Republican Party are saying and offering America.