Don't gloat, Democrats: Even if Clinton wins, your party has some major ideological splits to reckon with

“There will be a lot of people pulling on President Clinton for a lot of things,” said Representative Keith Ellison, a Minnesota Democrat who supported Mr. Sanders in the primary. “And absolutely everybody is going to have to be energetic in advocating for the things that they consider most important. But I think people like Elizabeth Warren and Bernie Sanders will have an advantage, in that we already have very progressive positions in the party platform.”

But Mrs. Clinton will also be under considerable pressure to accommodate moderate Democrats — and some Republicans — who gave her support, centrist credentials and money during the campaign. That includes Senator Chuck Schumer, her fellow New York Democrat who is in line to be the next majority leader if the party takes the Senate. Mr. Schumer has little interest in letting Mrs. Clinton and the party move to the left, given that Senate Democrats already face an uphill battle in 2018 to retain seats.

Any effort by Mrs. Clinton to court Mr. Trump’s supporters, as suggested by Mr. Dean, will have to be done delicately, given the concerns of Latino and African-American supporters, among others, who recoiled at the racially tinged nature of some of his appeals. Within her party, she is going to face conflicting demands from old-line liberal economists intent on bolstering the American manufacturing base against the new wave of Silicon Valley entrepreneurs who have a decidedly different view of the future of the American economy.