Bernie Sanders achieved a stun­ning and unprece­dent­ed vic­to­ry in Michi­gan Tues­day night, win­ning the Demo­c­ra­t­ic pri­ma­ry 50.1 per­cent to 48 per­cent and poten­tial­ly chang­ing the course of the pres­i­den­tial campaign.

Nate Silver of FiveThirtyEight noted that, before Bernie’s victory, “the candidate with the largest lead to lose a state in our database of well-polled primaries and caucuses was Walter Mondale, who led New Hampshire by 17.1 percentage points but lost to Gary Hart in 1984.” Now, that candidate is Hillary Clinton.

Sanders was expect­ed to lose Michi­gan by mas­sive mar­gins. While he has pulled sim­i­lar come-from-behind feats in recent weeks, from near­ly tying in Iowa to sweep­ing Min­neso­ta and Okla­homa — all of which were pre­dict­ed just a few days before­hand to fall into Hillary Clinton’s hands — Michi­gan rep­re­sents the largest turn­around yet. Real­Clear­Pol­i­tics’ aver­age antic­i­pat­ed a Clin­ton win by 21.4 per­cent.

Nate Sil­ver of FiveThir­tyEight not­ed that, before Sanders’ vic­to­ry, ​“the can­di­date with the largest lead to lose a state in our data­base of well-polled pri­maries and cau­cus­es was Wal­ter Mon­dale, who led New Hamp­shire by 17.1 per­cent­age points but lost to Gary Hart in 1984.” Now, that can­di­date is Hillary Clinton.

Of course, Tues­day night’s results rep­re­sent more than just one of the ​“great­est polling errors in pri­ma­ry his­to­ry.” They her­ald a new oppor­tu­ni­ty for the Sanders cam­paign, which in recent weeks has seemed to be floun­der­ing, fail­ing where it was expect­ed to lose but also fail­ing in states like Mass­a­chu­setts and Neva­da where it need­ed to win.

Pun­dits across the spec­trum have not­ed that Sanders needs some­thing to jolt his cam­paign back into gear — the Wash­ing­ton Post assert­ed on Mon­day that one of the rea­sons he lost Sun­day night’s debate in Flint, Michi­gan (whose coun­ty he won) was that he ​“failed to change the under­ly­ing dynam­ic of the race.”

That is no longer the case. Bernie has shift­ed expec­ta­tions and pulled the great­est turn­around of this race. Michi­gan shows that his cam­paign can con­tin­ue its prac­tice of defy­ing con­ven­tion­al polit­i­cal wis­dom in favor of a new and rad­i­cal mass politics.

The win also comes on the tails of increased Sanders fundrais­ing from his sup­port­ers, with the demo­c­ra­t­ic social­ist from Ver­mont out­rais­ing his estab­lish­ment oppo­nent for the sec­ond month in a row in Feb­ru­ary. He raised almost $40 mil­lion last month, includ­ing $6.4 mil­lion in the 24 hours after polls closed in New Hamp­shire on Feb­ru­ary 9. Sanders often makes a point of the fact that the aver­age dona­tion to his cam­paign is $27, an indi­ca­tor that he is is fund­ed pri­mar­i­ly by small donors.

How­ev­er, fundrais­ing alone won’t win him the nom­i­na­tion. Jeb Bush’s failed pres­i­den­tial bid in spite of mas­sive fundrais­ing has shown as much. Instead, Sanders has to con­vert the ener­gy from his lat­est vic­to­ry into momen­tum going for­ward. It is essen­tial that he con­tin­ue to defy expec­ta­tions in states vot­ing in what he calls ​“the most impor­tant sev­en-day stretch of our cam­paign.” These include Illi­nois, Ohio, Flori­da, Mis­souri and North Car­oli­na, all states where Sanders lags behind in the polls, and where a win would rep­re­sent yet anoth­er rebuke to the Demo­c­ra­t­ic establishment.

The wor­ry among Sanders sup­port­ers, of course, is that this will all be too lit­tle too late. Most media out­lets por­tray Clin­ton with a com­mand­ing lead in the del­e­gate count inte­gral to deter­min­ing the nom­i­nee at the Demo­c­ra­t­ic Con­ven­tion in June. She is pre­sent­ed as hav­ing more than twice as many del­e­gates — 1,221 to his 571, accord­ing to many counts.

Yet this num­ber is mis­lead­ing because it fac­tors in superdel­e­gates — par­ty lead­ers whose vote is decid­ed not by who wins in their state but by their own pref­er­ence. As these fig­ures are most­ly rep­re­sen­ta­tives of the estab­lish­ment, it is no sur­prise that Clin­ton has racked up 461 endorse­ments, and Sanders has only man­aged to gar­ner 25.

How­ev­er, it is extreme­ly unlike­ly that the superdel­e­gates would go against the can­di­date cho­sen by the pop­u­lar vote — to do so would be fun­da­men­tal­ly anti-demo­c­ra­t­ic and would trig­ger a major cri­sis in the par­ty. When the del­e­gate count is exam­ined with­out superdel­e­gates, it becomes clear that Clin­ton is only lead­ing by about 200 del­e­gates — still a siz­able num­ber, but by no means insurmountable.

If Sanders can con­tin­ue to defy expec­ta­tions in key states sim­i­lar to Michi­gan, and pick up enough small­er states on the way, he could well scrap his way to the Demo­c­ra­t­ic nom­i­na­tion — and change the nature of the Demo­c­ra­t­ic Par­ty while he’s at it.