BERLIN — That a small-town mayor turned MEP could be a serious contender for Germany’s chancellorship would rank as nothing less than a political earthquake — that is, if it weren’t for Brexit, Donald Trump or the sudden implosion of François Fillon in France.

In this zany political climate, Martin Schulz’s sudden surge in popularity is more par for the course than a surprise, the latest example of the punditry’s conventional wisdom being turned on its head.

Less than two weeks ago, the German press caricatured Schulz’s bid to resurrect his moribund Social Democrats as a kamikaze mission. With the party plumbing historic lows around the 20 percent mark — a full 17 percentage points behind Angela Merkel’s conservatives, Schulz’s decision to take up the party’s mantle looked to be an act of desperation by the man just ousted as president of the European Parliament.

As so often in Schulz’s unlikely political career, he is having the last laugh. News Monday that the SPD had overtaken Merkel’s Christian Democrats for the first time in more than a decade in a regular horse-race poll published by the daily Bild sent shockwaves through Berlin. A flurry of recent polls had shown the SPD gaining steam, but few believed the SPD would actually pull ahead.

The big question is whether the Schulz effect is sustainable.

The long shot that took the lead

Given the electorate’s fickle mood and Schulz’s new-man-in-town luster, the polls should be treated with caution. And yet, caveats aside, there’s no denying his candidacy has struck a nerve.

Up until two weeks ago, Berlin’s chattering classes believed a fourth Merkel term was inevitable. Love or hate her, Merkel was alternativlos, without alternative, as the common refrain had it. Though Merkel’s popularity suffered during the refugee crisis, her approval ratings rebounded as the influx dissipated.

Schulz, meanwhile, was widely dismissed as a long shot who lacked a strong network in his party and broad public support. About one-fifth of Germans said they didn’t know him. Even his campaign theme — social justice — seemed little more than a frayed socialist hand-me-down, further evidence of the party’s ossification and lack of vision.

The notion that Schulz could beat Merkel by running against the grand coalition his party has embraced — between the SPD and Merkel's conservatives — was dismissed out of hand.

No more.

If Merkel is still the front-runner, she’s running scared.

The upcoming campaign “will be the hardest I’ve ever experienced,” Merkel acknowledged on Monday in Munich.

A fractured base

Word that the SPD had pulled ahead in the Bild poll came just as the chancellor was trying to bury the hatchet with Horst Seehofer, head of the Christian Social Union (CSU), the Bavarian sister party to Merkel’s Christian Democrats.

Merkel and Seehofer have been at loggerheads for months over refugee policy, with the Bavarian pushing for a harder line, including a ceiling on asylum seekers, something the chancellor rejects. The ongoing tensions have allowed deeper divisions within Merkel’s base to fester, confounding Merkel’s attempts to rally the party’s conservative base behind her. While the CSU has pledged to support Merkel’s candidacy, a joint appearance with her and Seehofer in Munich on Monday did little to dispel the appearance of disunity.

Even Merkel’s allies are warning of Merkel fatigue. “Is Germany tired of Merkel?” the right-leaning Bild asked Tuesday.

To ask the question is to answer it. After 12 years of Merkel, many Germans are itching for a new face, if not a new approach.

Enter Martin Schulz.

While the Schulz effect may be more about appearance than substance (he has yet to present a program and his political positions hew close to Merkel’s), his energetic style and fresh face have resonated with voters hungry for a mainstream alternative to the chancellor and his predecessor as SPD chief, Sigmar Gabriel.

Germans view Schulz as untainted by the political compromises the party has made in the grand coalition.

Though Gabriel enjoyed strong backing within the SPD, his tendency to reverse course on important political questions cost him voter trust.

Indeed, what many observers saw as Schulz’s main handicap — his relative obscurity in German politics — is turning out to be his biggest asset. A Germany comedy show asked a random sample of German pedestrians this week what Schulz did before he became SPD chief. Most drew a blank. A young woman who professed support for Schulz couldn’t identify him in a photograph.

Making Europe Great Again

Even though he has belonged to the SPD’s senior leadership for years, helping to set the party’s direction, Schulz is viewed by many Germans as untainted by the political compromises the party has made in the grand coalition.

Conservatives have been trying to pour cold water on Schulz’s candidacy, describing him as an untested politician who knows more about Brussels than Germany. So far, the Christian Democrats’ attempts to discredit him, by drawing attention to his generous salary and perks as European Parliament president, for example, have fallen on deaf ears.

That may well change as the campaign heats up. But what worries Merkel’s camp is that Schulz’s strengths, his rhetorical skills and newcomer appeal, are qualities Merkel can’t match.

That’s already apparent on social media. A Reddit forum called the_schulz (a play on Trump’s “The Donald" moniker) has become a sensation, spawning a flurry of pro-Schulz memes and the acronym “MEGA,” for Making Europe Great Again.

Though half in jest, the often exaggerated testimonials, including regular references to Schulz as "Chancellor God,” are creating buzz around Schulz’s campaign, adding to its momentum.

Underscoring the importance social media is likely to play in the coming months, Schulz thanked his Reddit supporters with a personal video.

“You’ve unleashed a wave that is a big help for me,” he said. “I am aware of your support. It is engaging, creative and thoroughly enjoyable.”