Nicole Gaudiano

USA TODAY

PORTSMOUTH, N.H. — They spent more than a year trading barbs over both policy and judgement. But Hillary Clinton and Sen. Bernie Sanders worked to put that behind them on Tuesday, standing side-by-side in a high school gym as Sanders endorsed his former rival and told a cheering crowd that Clinton would “make an outstanding president.”

“She will be the Democratic nominee for president and I intend to do everything I can to make certain she will be the next president of the United States,” he said.

Clinton said her general-election race against presumptive GOP nominee Donald Trump will be more enjoyable now that she and the Vermont senator are on the same side. She urged Sanders' supporters to join her campaign and make it their own.

"We are stronger together," she said.

Sanders decision to finally endorse Clinton effectively ended his own own long-shot primary campaign, which defied expectations and tested the notion that Clinton’s claim to the Democratic nomination was inevitable.

10 quotable moments in Bernie Sanders' campaign

No additional joint campaign events have been finalized, and it's unclear what Sanders' role will be moving forward. A Clinton campaign official said Tuesday that more information will be released soon about Sanders' role at the Democratic National Convention in Philadelphia, where he'll presumably have a speaking slot.

Following his endorsement of Clinton, Sanders emailed his supporters asking them to sign a pledge to “continue the political revolution.” Rather than asking them directly to back Clinton, he instead urged them to stand with him against Trump and help elect progressive candidates.

In the coming weeks, Sanders wrote, he will announce the creation of successor organizations that will carry on the fight represented by his presidential campaign.

“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,” he wrote.

Though he has known Clinton for 25 years, Sanders has downplayed their friendship, telling NPR last year, “I’m not gonna tell you we are bosom buddies.” On Tuesday in New Hampshire, as Clinton stood behind him nodding her head, he said "it is no secret" that the two disagree on a number of issues.

But he said there was a "significant coming together" on the party's platform, which he described as "by far, the most progressive platform in the history of the Democratic Party."

Sanders told the crowd the next job is to see that same platform implemented by a Democratic House and Senate, and a Clinton White House.

“And I am planning to be in every corner of this country to make certain that happens,” he said.

Clinton noted that the two campaigns worked together on proposals she announced this past week. One would expand access to health care and the other would eliminate college tuition for working families.

Hillary Clinton offers health care proposal sought by Bernie Sanders

She called for action on Sanders' priorities, including raising the minimum wage, combating climate change, regulating Wall Street and reforming the campaign finance system, while reiterating her opposition to the 12-nation Trans-Pacific Partnership trade deal.

Over the years, she said she’s gotten to know Sanders as a colleague and friend.

“His reputation for passionate advocacy hasn’t always made him the most popular person in Washington,” she said. “But you know what? That’s generally a sign you’re doing something right.”

Clinton told Sanders supporters they will “always have a seat at the table” when she’s in the White House and asked them to sign up for her campaign.

“We accept $27-dollar donations, too, you know,” she said, a reference to Sanders’ oft-quoted campaign contribution average.

The line drew cheers. But the crowd at Tuesday's event included Sanders supporters — many holding his campaign signs — who seemed unwilling to accept Clinton as their nominee. When New Hampshire Sen. Jeanne Shaheen said "we need to elect Hillary," she was interrupted by shouts of "No!" and chants of "Bernie, Bernie."

“I’m a ‘Bernie or Bust’ person,” said Kathleen West, a farm manager from Gorham, Maine, who said she wanted to hear Clinton speak about her immigration policy and commit to supporting a $15 minimum wage. “I could possibly be swayed, but I want to see her not ride the fence."

Michael Blum, a software architect from Chelmsford, Mass., left the rally in protest. He said Clinton “doesn’t support us” and is only paying “lip service” to Sanders supporters.

“What does she stand for? Only flowery platitudes and ‘I’m not Trump’ – a stark contrast to Bernie and his issue-oriented message,” he wrote in a text.

Trump played off the disappointment felt by Sanders’ supporters, tweeting that he was “somewhat surprised that Bernie Sanders was not true to himself and his supporters. They are not happy that he is selling out!”

Trump hits Sanders over Clinton endorsement

In another tweet, he wrote: “Bernie Sanders endorsing Hillary Clinton is like Occupy Wall Street endorsing Goldman Sachs.”

In his email to supporters, Sanders acknowledged that some may be “disappointed” by his decision, but he said he believes their vision for a “transformed America” is best served by defeating Trump and electing Clinton.

“There is no doubt that the election of Donald Trump as president would be a devastating blow to all that we are fighting for,” he wrote. “I cannot in good conscience let that happen.”

Tuesday's rally in the Granite State, where Sanders trounced Clinton in the Feb. 9 primary and received more votes than any other candidate in the contest's history, recalled the moment in 2008 when Clinton and then-senator Barack Obama held their first large rally together in Unity, N.H., after Clinton conceded the Democratic nomination race to Obama.

Sanders will remain a candidate through the Democratic National Convention in Philadelphia, where he said the roll call will show he won almost 1,900 delegates — "far more than almost anyone thought we could win." Sanders' spokesman Michael Briggs noted that Clinton didn't release her delegates until the 2008 convention, where she interrupted the official roll call to move that Obama be selected by acclamation.

The lead-up to Tuesday's event, however, was very different from what happened in 2008. Clinton endorsed Obama shortly after the final 2008 primary. Sanders waited longer, resisting intense pressure to concede the nomination race in order to extract concessions from national Democrats regarding his top policy priorities.

Bernie Sanders defied expectations with long-shot presidential campaign

The platform that will be submitted at the party's convention later this month calls for a $15 minimum wage, expanding Social Security, abolishing the death penalty and breaking up large financial institutions — all staples of Sanders' agenda.

Sanders, who declared his White House bid on April 30 last year, passed on opportunities during the campaign to target Clinton's obvious vulnerabilities, such as the scandal involving her use of a private email server when she served as secretary of State.

But at campaign rallies, he targeted her donations from Wall Street and other special interests, and called on her to release transcripts of her paid speeches to Goldman Sachs and other corporations. Ahead of the New York primary, he alleged that Clinton wasn't qualified to be president — a statement he later walked back — after Clinton declined to say whether she thought Sanders was qualified.

Sanders also questioned Clinton's judgment based on her vote in favor of the Iraq War and her affiliation with a super PAC, and he criticized her decision to hold a “high-dollar fundraiser” at a hedge fund that invests in fracking, which he wants to end.

Clinton countered that Sanders wasn’t tough enough on guns, and she cast his policies as unrealistic. She said a widely criticized interview that Sanders gave the New York Daily News raised questions about his judgment, his ability to answer questions about foreign policy, and his understanding of the details involved in one of his core issues — breaking up big banks.

It’s still unclear whether the decision to endorse Clinton will sway Sanders' die-hard supporters — many of whom are young and independent — to support her. But recent polls show most Sanders supporters are ready to back Clinton over Trump.

In the last two days, progressive groups announced their support for Clinton, including Democracy for America, which had endorsed Sanders.

Charles Chamberlain, DFA’s executive director, said in a statement Tuesday, “We're backing Hillary Clinton in the race for President because she gives our country the opportunity to smash one of its last great glass ceilings and will be the partner we need in the White House to realize the agenda that Bernie Sanders's political revolution fought for in the primaries — from tuition-free college to Social Security expansion.”