He’s probably right on that count. I would bet that Trump will lose, and I’d even give two-to-one odds. But I remember how my mother in 1980, as a fan of President Carter, was overjoyed when Reagan became the Republican nominee since she figured that assured Carter’s re-election. She wasn’t so happy a few months later.

Presidential campaigns are driven in part by surprises: What if there is a new wave of Central American refugees, or a terror attack by a Muslim recently admitted to the U.S.? Either would bolster Trump’s chances.

The success of both Trump and Sanders this year should inspire humility on the part of all of us about predicting election results. I agree with Nader that it’s almost unthinkable for Trump to be elected. Then again, it once was unthinkable that he would win the Republican nomination.

Sanders supporters should also remember that they agree at least in part with Clinton on Wall Street excesses, income inequality and college debt. Likewise, whatever their distaste for the Clintons, they probably share her views on reproductive health, on Supreme Court nominees, on inclusiveness toward Muslims and Mexican-Americans, on immigration reform, on early-childhood investments, on a stronger social safety net, on women’s rights around the world, on reducing mass incarceration and on a global pact to confront climate change.

Senator Jeff Merkley, an Oregon Democrat who has been the only senator to back Sanders, acknowledges that now “we have a nominee.” He tells me that Sanders will continue his primary race through the Washington, D.C., vote next week but ultimately will focus on party unity.

“When I talked to Bernie when he was first thinking about running, he made it absolutely clear that he didn’t want to do anything that would result in the journey that we experienced with Ralph Nader,” Merkley said. “He will do everything possible to make sure that Trump is not in the Oval Office, and to do ‘everything possible’ certainly means that we’ve got to come together not just as a formality but in an inclusive, emphatic, unified fashion.”

In 2008, at about this time, Clinton stepped up and gave a powerful endorsement of Barack Obama. But she and Obama agreed on almost everything, while Sanders disagrees with Clinton on some issues and still exudes scorn for the Clinton campaign.