The formal answer to the question of whether Vermont Senator Bernie Sanders would endorse former secretary of state Hillary Clinton was answered Tuesday morning in New Hampshire. He did. With the presumptive nominee of the Democratic Party at his side, the insurgent contender announced that “Secretary Clinton has won the Democratic nominating process, and I congratulate her for that. 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.”

“I have come here today not to talk about the past but to focus on the future. That future will be shaped more by what happens on November 8 in voting booths across our nation than by any other event in the world. I have come here to make it as clear as possible as to why I am endorsing Hillary Clinton and why she must become our next president.,” the senator told a crowd in which a number of Sanders backers were still waving their “a future to believe in” signs.

What Sanders said Tuesday, and how he said it, was watched closely by political insiders who have for more than a year struggled to understand where the independent senator who entered a Democratic presidential race has been coming from. Fair enough. With that said, however, the announcement was not exactly a shocker.

Sanders spoke well of Clinton on Tuesday—telling the crowd in New Hampshire: “I have known Hillary Clinton for 25 years. I remember her as a great first lady who broke precedent in terms of the role that a first lady was supposed to play as she helped lead the fight for universal health care. I served with her in the United States Senate and know her as a fierce advocate for the rights of children.” But Sanders has a history of speaking well of Clinton. In 2014, when he was only pondering a candidacy, the senator told The Nation, “Look, I am not here to be attacking Hillary Clinton. I have known Hillary Clinton for a number of years; I knew her when she was first lady a little bit, got to know her a little bit better when she was in the Senate. I like Hillary; she is very, very intelligent; she focuses on issues.”

The point of a Sanders candidacy was never to attack Clinton. It was to take on status-quo politics in general, and to argue for “an alternative set of policies that says to the American people: with all of this technology, with all of this productivity, the truth of the matter is that the average person in this country should be living better than ever before—not significantly worse economically than was the case thirty years ago.”

Sanders proved to be dramatically more successful as a presidential contender than his detractors, or most of his supporters, anticipated. On Tuesday, he observed: “Our campaign won the primaries and caucuses in 22 states, and when the roll call at the Democratic National Convention in Philadelphia is announced it will show that we won almost 1,900 delegates. That is a lot of delegates, far more than almost anyone thought we could win. But it is not enough to win the nomination. Secretary Clinton goes into the convention with 389 more pledged delegates than we have and a lot more super delegates.”

But, Sanders also noted, Clinton goes into the convention with a proposed platform that reflects the values and ideals of the Sanders campaign on a host of issues.

“It is no secret that Hillary Clinton and I disagree on a number of issues,” Sanders said Tuesday. “That’s what this campaign has been about. That’s what democracy is about. But 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. Our job now is to see that platform implemented by a Democratic Senate, a Democratic House and a Hillary Clinton president—and I am going to do everything I can to make that happen.”

Clinton embraced the themes of that platform in a speech that hailed Sanders “not just for your endorsement, but for a lifetime of fighting injustice.” The presumptive nominee’s comments detailed areas of agreement between the candidates on what have been flashpoint issues—included a pointed reference to the need to say “no to bad trade deals and unfair trade practices, including the Trans-Pacific Partnership.”

Addressing Sanders supporters, a grateful Clinton declared, “You will always have a seat at the table when I am in the White House.”

Clinton was gracious, as was Sanders. Their joint appearance did not heal every wound or close every divide in the Democratic Party, but it set the agenda for a fall campaign in which Sanders says he will be on the trail nationwide—advocating against Trump and for Clinton.

The Sanders endorsement was newsworthy, to be sure.

But there was less mystery in it than late-to-the-game pundits might have imagined. Even before he announced his candidacy, Sanders explained that he would do what he thought necessary to prevent a right-wing Republican from winning the presidency.

Early in 2014, long before Sanders decided to enter the presidential race, the senator told The Nation, he was wrestling with whether to run as an independent, to run as a Democrat or to run at all. But he was certain about one thing: He did not want take actions that might hand the presidency to a Republican.

“Since I’ve been in Congress, I have been a member of the Democratic caucus as an independent. [Senate majority leader] Harry Reid, especially, has been extremely kind to me and has treated me with enormous respect. I am now chairman of the Veterans Committee. But there is no question that the Democratic Party in general remains far too dependent on big-money interests, that it is not fighting vigorously for working-class families, and that there are some members of the Democratic Party whose views are not terribly different from some of the Republicans. That’s absolutely the case,” said the senator. “But the dilemma is that, if you run outside of the Democratic Party, then what you’re doing—and you have to think hard about this—you’re not just running a race for president, you’re really running to build an entire political movement. In doing that, you would be taking votes away from the Democratic candidate and making it easier for some right-wing Republican to get elected—the Nader dilemma.”

That dilemma, Sanders explained, involves the structural challenge of getting attention and political traction for third-party or independent runs in a political system where political and media elites constantly reinforce a two-party system—and where they generally succeed in convincing the vast majority of November voters that they cannot risk backing an alternative candidacy. Recalling the 2000 presidential race, in which consumer activist Ralph Nader mounted a serious bid for the presidency on the Green Party line, Sanders said, “If you look back to Nader’s candidacy, the hope of Nader was not just that he might be elected president but that he would create a strong third party. Nader was a very strong candidate, very smart, very articulate. But the strong third party did not emerge. The fact is that is very difficult to do.”

Sanders was not playing blame games or telling others what approach to take. He wasn’t trying to defend a two-party system he has frequently challenged. He was speaking for himself—from a place of historical and personal experience. “That idea has been talked about in this country for decades and decades and decades, from Eugene Debs forward—without much success,” he said of independent and third-party presidential bids. “And I say that as the longest serving independent in the history of the United States Congress. In Vermont, I think we have had more success than in any other state in the country in terms of progressive third-party politics. During my tenure as mayor of Burlington, I defeated Democrats and Republicans and helped start a third-party movement. Today there is a statewide progressive party which now has three people in the state Senate, out of 30, and a number of representatives in the state Legislature. But that process has taken 30 years. So it is not easy.”

The bottom line, which Sanders made in a number of ways and in a number of interviews, was that he would not risk tipping a November race to the candidate of a Republican Party with an “ideology of tax breaks for the billionaires and cuts to every program that is a benefit to the American people.” This was why the long-time independent ultimately decided to run as a Democrat. That did not sit well with advocates for independent and third-party politics, and his endorsement of Clinton on Tuesday frustrated them. Green Party presidential candidate Jill Stein, who had urged Sanders to reject Clinton, expressed disappointment in the endorsement and made a pitch to Sanders backers Stein argued that “we can’t have a revolutionary campaign inside a counter-revolutionary party.”

But Sanders had, throughout the 2016 campaign, signaled that he was not going to exit the Democratic camp after running in the party’s primaries and caucuses. As a 2016 candidate, Sanders detailed his objections to the centrist compromises of prominent Democrats. But he was always blunt and aggressive in ripping on Republican leaders and funders, saying “they want to give more tax breaks to millionaires and billionaires at a time when the rich are getting much richer” and that “they want to cut or privatize Medicare, cut Medicaid, cut Education, cut the Environmental Protection Agency.”

As it became clear that Donald Trump would be the Republican nominee, Sanders made it clear that defeating Trump was not just a priority but a moral and practical necessity. Highlighting an issue on which Clinton has moved toward his position, Sanders told the crowd Tuesday in New Hampshire:

Hillary Clinton understands that we must fix an economy in America that is rigged and that sends almost all new wealth and income to the top one percent. Hillary Clinton understands that if someone in America works 40 hours a week, that person should not be living in poverty. She believes that we should raise the minimum wage to a living wage. And she wants to create millions of new jobs by rebuilding our crumbling infrastructure—our roads, bridges, water systems and wastewater plants.

But her opponent—Donald Trump—well, he has a very different view. He believes that states should have the right to lower the minimum wage or even abolish the concept of the minimum wage altogether. If Donald Trump is elected, we will see no increase in the federal minimum wage of $7.25 per hour—a starvation wage.

This election is about which candidate will nominate Supreme Court justices who are prepared to overturn the disastrous Citizens United decision which allows billionaires to buy elections and undermine our democracy; about who will appoint new justices on the Supreme Court who will defend a woman’s right to choose, the rights of the LGBT community, workers’ rights, the needs of minorities and immigrants, and the government’s ability to protect the environment.

If you don’t believe this election is important, take a moment to think about the Supreme Court justices that Donald Trump will nominate, and what that means to civil liberties, equal rights and the future of our country.

No one imagines that Sanders is satisfied with the Democratic Party or American politics as it now stands. But Sanders has believed for a good long time that the Republican Party has “moved to become a right-wing extremist party [and that] their goal is to repeal virtually every major piece of legislation passed since the 1930s to protect the elderly, the sick, the middle class, and the poor.” And he has always been quite clear about his intention to prevent that party from winning the White House.