PHILADEL­PHIA — Bernie-or-Bust is big­ger than any­one bar­gained for. And nei­ther Hillary Clin­ton nor Bernie Sanders has yet fig­ured out a way to make it smaller.

"As Sanders takes a backseat in the political revolution, the question now is who can keep it from driving off a cliff."

The ardent sup­port for Sanders — against Clin­ton — has tak­en just about every­one at the Demo­c­ra­t­ic Nation­al Con­ven­tion off guard. For months it’s been easy enough, espe­cial­ly on the left, to pass off Bernie-or-Bust as a trumped-up fab­ri­ca­tion by dis­con­tent­ed Clin­ton vot­ers and a main­stream media out to bol­ster the establishment.

But the anger and dis­il­lu­sion­ment at the con­ven­tion are real. As is the promise, from some, to not vote for Clin­ton come November.

I met Gabriel McArthur, a Sanders del­e­gate from North Den­ver, short­ly after he’d fin­ished chant­i­ng out­side Sanders’ speech to his del­e­gates Mon­day after­noon. McArthur, 24, ran in his Con­gres­sion­al dis­trict to become a del­e­gate after find­ing Sanders on an iside​with​.com quiz.

He sees vir­tu­al­ly ​“no hope” in Sanders’ chances at win­ning the nom­i­na­tion, adding: ​“It’s not going to keep me from talk­ing to peo­ple about it.” His top cri­te­ria in choos­ing can­di­dates is whether they stand by their values.

“He’s con­sis­tent,” McArthur said about Sanders.

He says he won’t vote for Clin­ton, and is mulling over the pos­si­bil­i­ty of sup­port­ing Green Par­ty can­di­date Jill Stein.

McArthur isn’t alone. Between Sanders get­ting shout­ed down by his own del­e­gates, to a nascent attempt by post-Occu­py groups to walk out on the DNC, and the BER-NIE chants and boos that rung through the con­ven­tion cen­ter dur­ing Monday’s speech­es, it seems there are many, many thou­sands of peo­ple with no inten­tion of vot­ing for Clinton.

Nor do those peo­ple seem will­ing to take to heart come­di­an Sarah Silverman’s admon­ish­ment at the con­ven­tion: ​“To the ​‘Bernie or Bust’ peo­ple, you’re being ridiculous.”

Of course, what can be gleaned from the Demo­c­ra­t­ic Nation­al Con­ven­tion is a sam­ple size, at best. Thir­teen mil­lion peo­ple vot­ed for Sanders. Accord­ing to a recent Pew Research Cen­ter poll, 90 per­cent of them say they will back Clin­ton in Novem­ber. Still, more than a mil­lion defec­tors are hard to ignore — espe­cial­ly with the pos­si­bil­i­ty of Don­ald Trump tak­ing over the White House.

“A sub­stan­tial num­ber of Bernie del­e­gates are so loy­al to him and so unhap­py that they’re not hear­ing him,” says Dan Can­tor. ​“Right now there’s a lot of anger … A sub­stan­tial chunk of Sanders del­e­gates are not yet think­ing strate­gi­cal­ly and seri­ous­ly about the stakes here.”

Can­tor — the nation­al direc­tor of the Work­ing Fam­i­lies Par­ty, which vot­ed to endorse Sanders back in Decem­ber — sees room for improve­ment on both Sanders’ and Clinton’s parts.

“Sanders needs to make the case to his own base,” Can­tor said yes­ter­day, ​“that the polit­i­cal rev­o­lu­tion he wants to con­tin­ue will have a much bet­ter chance to flower with Clin­ton in the White House, no mat­ter how imper­fect her admin­is­tra­tion will be.”

Clin­ton, Can­tor advised, ​“needs to ele­vate issues like the Fight for $15, like col­lege afford­abil­i­ty, like racial jus­tice and fight­ing cli­mate change and invest­ment in job cre­ation — places where she has moved toward Sanders. She has to give peo­ple a rea­son to believe that, at least in part, she is car­ry­ing for­ward Sanders’ mission.”

Clin­ton has been treat­ing the race as over since she won Cal­i­for­nia in the pri­maries, piv­ot­ing — as we saw last night — to mak­ing a show of Trump’s vul­gar­i­ty and aller­gy to the polit­i­cal­ly cor­rect: death to neo-fas­cism by a thou­sand fact checks. Sanders’ speech to his del­e­gates yes­ter­day after­noon — what could have been his chance to make a dif­fi­cult, hon­est speech about his com­mit­ment to defeat­ing Trump — repeat­ed the same tirades against the mil­lion­aires and bil­lion­aires he’s made through­out his cam­paign. His pitch for Clin­ton was an after­thought and went over just about as well as it could have to a crowd that for months has seen Clin­ton as pub­lic ene­my No. 1.

For many Sanders sup­port­ers — del­e­gates includ­ed — his cam­paign was their entry into pol­i­tics writ large, along with the Demo­c­ra­t­ic Par­ty. That some tied their hopes to a rev­o­lu­tion by Novem­ber isn’t entire­ly sur­pris­ing, and nei­ther is their dis­ap­point­ment that the par­ty couldn’t deliv­er. Speak­ing at the con­ven­tion last night, Sanders stressed the polit­i­cal rev­o­lu­tion, ​“Our Rev­o­lu­tion,” as he calls it, would car­ry on.

“This elec­tion is not about, and has nev­er been about, Hillary Clin­ton, or Don­ald Trump, or Bernie Sanders or any of the oth­er can­di­dates who sought the pres­i­den­cy,” he said. ​“Elec­tion days come and go but the strug­gle of the peo­ple to cre­ate a gov­ern­ment that rep­re­sents all of us and not just the one per­cent … that strug­gle con­tin­ues. And I look for­ward to being part of that strug­gle with you.”

Although his speech­es Mon­day like­ly won’t con­vince every Bernie-or-Bust sup­port­er, Sanders tried to give his fans a frame­work for under­stand­ing what comes next — not Bernie in the White House, but the slow­er and less glam­orous work of build­ing a move­ment out­side the spot­light of a pres­i­den­tial race.

After all, steer­ing the Demo­c­ra­t­ic Party’s angry Bernie-or-Bust base away from apa­thy, nihilism and hope­less Green Par­ty fights — indeed, fight­ing the threat Trump pos­es to the country’s most vul­ner­a­ble com­mu­ni­ties — has nev­er been up to politi­cians. In this elec­tion, it’ll be up to the mil­lions of donors, hun­dreds of thou­sands of vol­un­teers and social move­ments that brought Sanders to Philadel­phia in the first place.

In con­trast to the Repub­li­can Nation­al Convention’s eerie sin­gu­lar­i­ty, the DNC has been a messy demo­c­ra­t­ic exper­i­ment con­duct­ed by a slew of actors, most of whom aren’t used to hav­ing a man on the inside. Not every­one is think­ing strate­gi­cal­ly, though many are; some are think­ing dan­ger­ous­ly. As Sanders takes a back­seat in the polit­i­cal rev­o­lu­tion, the ques­tion now is who can keep it from dri­ving off a cliff.